Excellent advice from Bockman and others, but I'd like to add one thing: USE THE LEVERS.
I can usually do mountain bike tires without them, but at the first hint of resistance, I go for the plastic.
I don't know how many tubes I've patched or tires I've changed, but I've been riding for 30+ years and have had as many as 13 bikes in the garage (two kids, mountain and road for each, plus my wife, plus whatever I've picked up somewhere). I probably average at least a flat per week and have had as many as six in a single century. In all that time, I can remember ONCE when I pinched a tube with a lever, and that was when I thought, "I might have caught the tube in there...ah, probably not."
Man is a tool-using animal. Don't be left out.