High altitude baking

Hey Just Bento, I was kind of hoping to find some tips on baking at high altitudes. I live in Colorado, so baking is always tricky. I know that when you bake things from a box they tell you to add some flour, but I was wondering if there were other rules that like that I should keep in mind for general baking. Also, how much flour, ratio-wise, should you add to a recipe? In particular, I've had a lot of trouble getting bread to rise. It just sorta...deflates after I pick it up again. I'm good at cooking, but I suck at baking, so any general baking advice would help, too. I don't have a bread maker or any fancy equipment, since I'm just a college student with no money. Thanks for your help. :)