While on the subject...

Well for myself, my first map was a simple bridge, I changed it probably 20times before I even tried to playtest it. While I wish I did a design document and sketches now, the way I figured out what to do was put myself in the players shoes, not my own "trying to figure out what works as a mapper" shoes. If you pretend like you are playing the map, say you peak over a corner in a hall, what will you want that individual to expect? Open area? Sentry farm? fight? control points? If there was a sniper lane, (it was a bridge after all) I asked myself as a player what I would want to keep myself from being shot from an imaginary sniper. I decided to put cover down but not just regular cover I tweaked it so snipers wouldn't get the opportunity to snipe, at least not very well and it made my bridge into a wonderful charge to the cp without worrying about overpowered snipers. After a while I finally released a playable version and much to my surprise the issues with the map didn't turn out to be game play (which everyone assumed would turn into a sniper fest) it turned out to be my optimization lol, but that's not the point. Basically, just keeping going, get feedback from yourself as a player and feedback from the community. Ask what you want to see while running around, and don't just go scout either you have to experiment with the other classes too.

As for the compiler, run with no rad and no vis, and make sure it can just compile completely. If it can, chances are you need to optimize.

For the optimization:

http://optimization.interlopers.net/