Don't underestimate the power of the Flag... call it first thing, pick it up, and carry with you everywhere. That way, all new troops come to you so you don't have to run back and forth.
Also, you'll need one of those big hulking tank things... probably a few of them, so always have one on reserve. FireBike things where my second favorite unit.
I always started off by pumping out a bunch of headbangers and two healing bass playing thing-a-ma-jigs. Then I went and told them to attack every fan gyser I could find right from the start. If a previous gyser went under attack, I didn't worry about it. I'll go back and get again later... the computer isn't that smart.
Once the fans are pulling in, I'd set up shop in the middle of the map to deter future attacks while I upgraded the stage and built those huge tank things. Then I just kicked a lot of ass.
never found it difficult to be honest... then again, I played a lot of Starcraft growing up.