Twilight Sparkle prides herself on following and sticking to her plans, but she isn't as organized as everypony thinks. Her master list, the plan for her life, has an item that she has never been able to check off; and the time has come to fix that. How hard can it be? All she needs to do is go on a date and get a kiss.

Now available in hard or soft cover!

Twilight always thought that being able to send the Princess her letters instantaneously through Spike's fire breath was the best thing in the world. Instant correspondence with her mentor and secret crush could never be a bad thing, right? Unfortunately, Twilight has a habit of writing her secrets down on flammable materials. Now her secret's out, so what's a panicky unicorn to do? Panic, obviously!

Twilight Sparkle is summoned to settle a legal matter involving The Great and Powerful Trixie... What in Equestria did she do now?

Fluttershy comes to Rarity looking for advice on what to do about an unrequited crush ... but Rarity has a few secrets of her own, and may not be the right mare to ask after all.

A thousand years is quite the generation gap, so Princess Luna decides she has to get with the times. However, this isn't quite as easy as she thinks it will be...

Twilight becomes alicorn of the stars. This is sort of a problem, because Luna kind of already was alicorn of the stars. Oops!

TV Tropes

In which I, Twilight Sparkle, (the biggest idiot in Equestria), fail miserably, utterly, and conclusively in my valiant endeavor to keep my decidedly-more-than-Friendship feelings hidden from one Rainbow Dash (the sexiest fastest mare in Equestria).

The following transcripts are of a journal found in Ponyville on April 16th of this year. The last recorded contact with the town had been 3 days prior, on the 13th, when a team under orders from Princess Celestia was sent to look into several missing pony reports in the area. When another group of investigators were sent on the 16th, the town was found deserted. The journal’s owner is believed to be the princess’s personal student, Twilight Sparkle. None of the town’s inhabitants have been located in the weeks since.

Readings:
Nimbus Productions
Scribbler Productions

I highly recommend both of them.

A print version of all the stories in this series can be found here.

Princess Celestia tires of constantly being surrounded by decorum, deference, and formality, and decides to take a day off from being Princess. But visiting Ponyville incognito is harder than she expects. Will she be able to fit in and make friends without blowing her cover?

One by one, Twilight and her friends must come to terms with the consequences of being the Elements of Harmony.

These stories take place in the intervening time between Season One and Season Two,
with the exception of Ditzy Doo: Muffins, which takes place early in Season One.

The series continues in the sequel, Secrets and Lies.

Pony Psychology has a TV Tropes Page.