When I got started, I read every post ever made in this forum, starting from the beginning. It took a good little while, and some of it didn’t make sense, but after a while I had one of those “ah-ha” moments, and felt like I could get started.
In terms of what to watch out for…most PPC engines are a bad investment, and the folks selling “targeted traffic” are ripping people off, so be really careful of them and stay far away from them. (I have some luck with espotting and 7search.com, but others here don’t even recommend them.)