I am in the same boat, but I do read about ironing. (Like cooking - can't do it, but I read about it.) One thing you might try is a firmer ironing board. Less batting under the ironing pad.
I also read that as soon as you press a seam, lay your ruler on it until it cools. That's supposed to keep it flat.
As for half square triangles, the Bloc Loc ruler makes sure the seam is perfectly straight, preventing some types of wrinkles.