Simple question: Does it have any sort of effort put into it?
That's pretty much it. If you actually put an effort into making something decent, odds are it'll be welcome (with more or less criticism, depending on the end result).
What's generally unwelcome here:
- Maps clearly puked out in 2 mins (fullbright, non-functional, squares with nothing in them, etc).
- Orange maps (not maps using dev textures, most of us use them at some point, but maps finalized as dev textured... It's just lazy).
- Gimmicky edits of previously existing maps that aren't clearly satirical ("HEY GUYSE, LOOK 2FORT WITH CHROME TEXTURES! 2COOL MORE LIKE IT, AMIRITE?!", "BADWATER WITH NIGHT SKY! I'M 2 SEXY!!", etc).
... In other words, it doesn't have to be a "traditional" map, just has to show you were at least trying to make something decent. Just don't toss the mapping equivalent of "shovelware" at us and expect us to accept it. That's all.