Help with some AI

Im participating in the hero creation contest, and i am in need for further balance testing, so, lets say i got an archmage. I want the archmage to use the most human-like strategy of spells on my hero (water element+then blizzard me), then, use stuff again when the cooldowns are finished. Then i want to do the same with all the other heroes in wc3.

My problem is i have never made any AI before, so i ask for some help.