Well, there are a lot of things that cause crashes, it's mainly because of a compile gone wrong. If your game is crashing, make sure to launch the game manually, not from Hammer.

Turbosmooth dat shit.

There are MANY reasons. Hammer crashes just like any other program, either it runs out of memory or it encounters a glitch. As for a map crashing your CS:S, thats a specific problem, so make sure to post the compile log of the map that is causing you trouble and we will take a look at it.

I have a girlfriend, lolwut?

Im looking only for a list of "dont do..." so i can keep it as reference and also show it to new map makers i am introduced to.

Ok before you click OK on the compile make sure there is a check bocks and it says don't run the game after compiling