I need tips about how to make the computer "smart"
depends what you're trying to achieve (the purpose of the improved 'computer')
yea it depends but in normal sc maps... just use the AI script insane they should be pretty smart for sc......
but to tell you the truth if you want them to be real smart you make all the triggers

ok ill make lots of triggers
Just run an ai script, each one does special things
like area town (i think that what it called) is mainly for a mining base (i think, not sure)
but yea each ai script does something nice and special
Really it depends on what for. In a melee style map, AI scripts should probably be doing what you need.