Read the forums AND try out changes on your own. The best way to learn is through experience. I dont know how many times I run into people who need tuning suggestions, and they cant remember what I suggest 5 minutes later. You need to know about the tables and what they mean to fully understand what people tell you. Do you understand the PE tables, IFR tables, MAF tables, what your fuel trims mean, VE tables, VE, A/F Ratio, etc? If you dont, then no matter how much someone shows you, you wont remember because you wont understand.
If you have a Powrtunr, there are detailed write-ups (60+ pages) about the different tables, different tuning methods, and more on the DHP Forum. If you bought a HPTuner, then that was your first mistake. If you have neither, then you arent tuning
Mike