I did a google search and I found a ton of tutorials that I liked, so I felt like sharing them here! Links are added beneath, just in case the hot-linking fails. Note: I didn't draw any of these.

You can click an image in this post to make it bigger, but clicking the link should allow you to view the largest available size. This is especially useful for reading some of the text. (I keep adding stuff to this post, btw. )

This link goes to a rather extensive visual guide regarding the show's official pony proportions.

Turnarounds.

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I mostly like this for the beautiful forelegs in the right corner.

Very handy!

Side View vs. 3/4 View

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Forelegs

Hind Legs

Link. Realistically, a pony should be on his or her side when they're lying down with their hind legs extended. It's possible to put them flat on their stomach in this circumstance, but it tends to look strange for a true quadruped, so it may look strange for a pony. Ultimately, you have to decide what's right for your drawing, but it's worth keeping in mind.

Rainbow Dash wants to model this for a moment.

I like the suggestions for the neck, ear, and muzzle placement.

The neck changes somewhat when they're running. I think it may depend on how the head is positioned, if it is lowered, though I feel curving the throat inward would look more elegant. But the show doesn't exactly do that.

Holding the head downward is more natural than having it held up high, if they're going at a significant speed. The mane and tail also tend to fly back if they're going really fast. And though it might have intensity, showing movement from a frontal view doesn't have the same solid silhouette impact, so it tends to look bad in a single, still image. For that reason, running and walking tend to be more interesting from the side or a 3/4th view.

Also, keep in mind that walking and running are a balancing act, even if we do it every day. Unbalancing a pony will make them fall over, though the more legs that are touching the ground, the harder it is to lose balance. If you're doing a walking/running pose, it's never a bad idea to use some sort of reference.

Walk Cycle. The dots at the bottom are showing which hooves are touching the ground.

Another Walk Cycle

Walking, I think.

More Walking. Hopefully this is okay. The rider is nude but you can't see anything naughty.

Jumping and also some humor, apparently.

Running, I think.

More Running.

Galloping

More Galloping

Another Gallop

This page includes a download for a full file of vector traces. The artist has also made some other vector bases, which are uploaded to this Deviant Art account.

Poses! Center of balance is really important. I'll need to find a better guide for that some other time.

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This is accurate.

Can you handle the details! Well?

Because wings can be complicated if you're doing any pose in-between extended and folded.

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Also a more realistic approach.

This is more about birds overall, but the parts that discuss the wings have some great tips to keep in mind. Obviously pony wings tend to be a lot less complex, but it helps if you feel like getting more detailed or have a complicated pose in mind.

Basically, all wings are built like arms and have a similar range of movement.

This illustrates that a lot better!

This helps illustrate the similarities in human anatomy and animal anatomy, to make it easier to wrap your head around poses.

This does the same thing.

Note: Ponies seem to have shoulders with a range of movement much like our own, with a ball joint, despite the fact real horses don't really (their skeletons have some key differences that make this unlikely, anyway.) Always consider the ponies of FiM to be anthropomorphic when it comes to movement, but not everything looks perfect. Some arm/leg positions will look super strange if they're standing on four legs, but seem more natural if they're standing up on two. Also, be aware that the withers are the bottom of the shoulder blade; they aren't the shoulders in the strictest sense of the word!

Note that in spite of the fact part of the foreleg is called a "knee" it's not a true knee. People named horse parts weirdly in some cases. It's really more like our arm in range of movement, especially since the ponies are very humanized.

I found a much larger version of this image! It helps illustrate some of the underlying features. If you want to read the text, click on the link. It's huge.

Yay, these are good for something.

Berry Punch with more realistic anatomy. Actually, I think her anatomy is a hybrid of human and horse, given the thigh-shape.

Here are some anatomy for hooves. You don't need them to be super realistic for MLP, but it helps to understand the structure.

3/4th angle

Think of the part that the front hoof attaches to as the hand connected to a wrist. Also, the interior of the underside of the hoof has kind of a shallow concave shape.

Another simple view of the hoof, but turned the other way.The frog is the softer part of the hoof that isn't really covered in keratin, incidentally. You can ask The Sexy Assistant for more details.

A more simplified drawing of the frog. Think of it kind of like a paw pad, but with a more triangular shape. The frog does touch the ground as a pony walks. For a drawing, you don't really even need the frog, but if you want a more realistic detail, you can add it in.

Here are some color guides for some of the official characters in the show. They're all PDF files.

A guide for creating pony eyes in Illustrator! The summary has links to other useful tutorials by the same DeviantArt user.

Also there is this one, same user but not linked to I don't think, for the unicorn magic effect.

I never really noticed Rarity's hair had a gradient. While specifically Illustrator in nature, it could be useful. Rarity's hair is like one of those curled ribbons in design.

I never noticed this either! This is REALLY useful if you like the Pony Creator games for testing out a color scheme and general design, but it proves these aren't completely reliable, whether you're using vectors or not! (I knew the joints were messed up, but another tutorial in this post illustrates that.) Just be careful when testing stuff out this way.

Incidentally, I've got links to some color guides in this thread.

A Comprehensive Reference for Fluttershy's House! This same DeviantArt user has a bunch of other buildings too, including Sugar Cube Corner, the Library, and Carousel Boutique. These get updated as episodes add in more background information, but I'm not sure how frequently.

Incidentally, I looked at the sample pictures of the official "How to Draw MLP" book. That's what I was trying to look up when I embarked on this quest. I don't think it's worth buying, since the stuff online seems to be more in-depth and detailed!

2860921
I gave this a sticky post, and It will get a link in the bio of this group!

Pretty informative!

2860942 2860947
No problem! I sneakily edited in some more, btw. I can remove anything that doesn't seem fitting though.

2861013
the berry punch is creepy...

2860942 HaHa, I'm sticking to this. (what ever glue you used)
2860947 yeah, sure is interesting.
2861013 are you running for the office of head Tutor on Pony drawings?
if so, you may just have the best position to keep the post.

2861062
I didn't draw any of these images, but I'm willing to win the election!

2861185 to me, the important part is that you presented them in a possitive spirit.

now we have a good selection of turtorials to examin for future(further) refference, when we try to draw a poni.

Now we can go over these in great details.

2861036 why the 'Berry Punch'?

some of the other image have more 'Creep Factory' to them.
just look at the 'disected' ponies?
2861013 just add your best versions, and keep a link, if there is a larger image,
or is any other question to it?
2860947 I'd second the motion, it sure is.
2860942 sticky? now that's exciting.

2860921 The detail has been doubled!

2860921 Lots of really informative stuff in here for beginners and pros alike.

2860921 You receive all of my jelly. I'm really glad I advertised this group to you. This is truly a compliment to everyone and an intuitive compilation of images.

Errr... Celestia... You're skill makes me ill...

I'm in a good mood... Have some complimentary music:

Edit: Subtle head banging insinuates...

2862362
Eeep. Nope, I didn't draw these. I guess I better put that up at the top. But thanks for being pleased.

2862480 Shut up! I know you didn't draw these. I even used the second one as part of the banner.

I people are just happy to see a competent collection of images that provide a pragmatic tutorial. I pleased the first time you PMed me because you're comment was so convoluted and off-topic that you didn't want to post it in a thread.

Love you!

2862510
Oh! Okay. Well, you said your were jelly and I just didn't want to give the wrong impression.

But yay! Love you too.

I have a really bad habit of getting off-topic within threads.

2862755 You didn't. You're self consciousness has benefited you in this case.

I think we could get a ten page roleplay started here if you really wanted to.

2862808
Don't get me started! You know I could.

2863105 Admin banter! We should do that some other time...

2863154
We should.

I added some stuff on running, but I felt screencaps might be best in that instance. Good, bad, or needs some downsizing? Should I remove the image of Dash carrying that dude? It's not sexual, but I worry.

Should I find actual tutorials on that instead?

2861013 DAAAAAAMN!!!! This is in-depth! It's getting added to my bookmarks section for future reference...which will be like tomorrow since I'm starting work on a banner for Lord of Nothing...

2864001 I checked them out. They seem appropriate... I don't know how much people learn from gifs. I've tried myself, it's hard work.

It kind of reminds me of the gif where RD catches that guy at the gala... That looked a little dirty. This is fine though, unless you can find a better picture.

2868127
I'll look for a proper tutorial then and see what I can find.

2869288 Good Luck!

2869311
I found a little bit and added it in.

2872893 I saw the supplement. It's really good. I want your children...

2875438
Now I just wish I could find something pertaining to the stallions, since they have the most distinctive variations.

And where the center of balance lies in four-legged critters. That would be a very, very useful guide.

(Also you can definitely carry my children; I'll lend you my womb.)

I'll have a look myself. They do have a very particular facial type and form.

It's pretty central, around the arch of the back. If you've ever watched horse racing you'd know they can't lean much so it does vary very much either although they can rear up and buck etc. I'm not to sure.

(That makes me happy... but realistically I don't deserve you're children.)

2879458
I found one, but it was just a collection of references. I was also hoping for something that included the new body styles too. Might add it in later anyway.

Hrmm, that makes sense. We need something that illustrates both centers of balance (since the FiM ponies can rear up for a lot longer and technically achieve nigh human positions; so in some circumstances they have a human center, but normally just a horse center of gravity.) That might be too much to ask of a single guide though...

(That makes me happy... but realistically I don't deserve you're children.)

That's a good thing! No one deserves that level of unhappiness.