for me, i don't use ideas before i make my map. i start with one flag, then the room that houses the flag, then it all comes from there. don't forget to light it as it goes because it it a huge pain to light it all at the end.
Do you mean a counterstrike map? because you should start with a good unique map, actually a few maps with your own ideas, so you know what works and what doesn't. then maybe try to remake it if you ever do.