My general method was:

1. Play a good-aligned character with identify (or max lore).
2. Look at other good/neutral characters who would plausibly be friendly with me.
3. For any gear I didn't recognize, ask to borrow it and identify. Log the results.
4. Ask if they know where's it's from.

Alternate steps #1 and #2 from the above:

1. Play an evil character with identify (or max lore).
2. Look at characters who would plausibly be willing to let me handle their gear, e.g. someone in the same Empire sect, another Rager if I'm in Battle, another Trib if I'm in Trib, etc.

Somewhat more recently:

1. Scan the "eq freeze" section of prominent characters' PBF posts. Note any gear I don't recognize.
2. Ask via OOC channels, e.g. forums, with the expectation that gear from exploration areas won't be divulged.

Also, in general, try to get taken along when your allies go on gear runs. Helps if you're a class that's useful in PvE. Healer, bard, transmuter, invoker, etc.

Also- if you're a hero, sometimes you can "buy" information from lower ranked characters in exchange for getting gear for them.