The wiki, is of course, a great resource. I think the best thing I ever did for eq knowledge was to roll up a neutral/neutral utility/defense shifter and run around killing everything in sight and identifying it.

Somebody (twistedvoid, are you out there?) wrote up an app called CFI that was actually very nice, and very promising. It took logs, parsed out the id's, then inserted them into a database.

I think that might be overkill - but I think it's worth buying everything from every shop at least once and identifying it, just so you know what it does. Maybe keep a spreadsheet of some specific things as well.

Overall though, experience is it. The good news is that things are always changing and new equipment appears more often than you'd expect, so the playing field is more level than you might be led to believe.