Cyclone wrote:What kind of pitfalls do you mean?
Some common ones:
1. Wrong level of challenge (and possibly reward).
2. Too much desire to add completely new things. Especially vault-defined monsters and explicitly specified items.
3. Reliance on gimmicks, such as lua triggers.
These all come from new vaultmakers wanting their vaults to be very special, and different from what's already in crawl. Not necessarily a bad thing, but combined with inexperience the resulting vaults are frequently terrible. Some of Grunt's vaults are perfect examples of this.
If you want to avoid these problems, make a few vaults where you only use random monster glyphs, not too many out of depth monsters, and no lua. Vaults (the branch) rooms might be a nice place to start. Once you know how to make these fun, you can more safely move on to fancier stuff. If you want some strong opinions on this (and good advice on vault making) you should talk to tenofswords or st in ##crawl-dev, or you can read tenofswords in progress vault making guidelines. I can dig those out if you want.
Cyclone wrote:I think it depends on what you want to make. Sprint was designed for short levels, but there's nothing wrong with having some longer ones.
The sprint game mode is called sprint. As in fast and short. It's okay to have some variety, but it would be weird to have some completely atypical sprint maps. When a player chooses to play a sprint map, the player should get what it says on the label, not something completely different. However, if what you design is fun, I'm sure space will somehow be made for it.