i learned to map, when there were no "crutches" such as hints and so forth.
my advice. try trial and error. learn exactly what makes the frame rates drop.
start with your hardware. is it substandard? if not, then assume its your mapping habits.
mapping habits will be your biggest hurdle to overcome, because if you are like most of us, you will always assume that you cannot do better. that "THIS" is as good as it gets. WRONG!
learn to map smaller, making areas with 1/2 of your intended size. examine each compile to note what went wrong, and why. COMPILE FREQUENTLY!!!!
learn how architecture effects frame rates. learn how scale effects frame rates. learn how distance effects frame rates.
lastly, and with the HL2 engines capabilities... learn what entities effect frame rates. a bunch of toilets and radiators being flung around will definitely effect them.
/ 2 cents.
[addsig]