More may be added as I think of them.

1. Don't worry too much about getting it done on time. The deadline for each story to be submitted is the last day of the month, give or take a few hours due to timezone differences. In other words, you've got the whole month to write!

2. If you've ever had writer's block, write out an outline. An outline can really help, even with one-shots, when you know where you want to go but not how to get there.