I just found this great video on another woodworking site about building basic skills. The fellow who made it is a professional woodworker, and he has a pretty well equipped shop. But in this video, he's showing how to build some basic skills in a minimally equipped shop (a pair of sawhorses in his basement).
He has a quick video on flattening a board, starting from rough stock. That's wood that's straight from the saw, not with the smooth surface that you see in the lumber racks at the big box store. He's showing a collection of four planes in use, which would be expensive if bought new, but if you buy on ebay you can pick up the whole set for about the price of a compressor and nailer combo (if you're my dad, you can pick them up at garage sales for about the price of a trip to a breakfast buffet).
http://www.finewoodworking.com/item/35868/video-how-to-flatten-wide-boa…
Why is this skill important? First, because you can save a lot of money on wood by buying rough stock instead of already surfaced.
Second, because even the surfaced stock sold in the big box stores or the lumber yard are imperfect. It's cupped, it's twisted, it's generally problematic. But with the fairly simple skill he shows in the video, you can fix that problem and you'll have a much easier time building furniture.