Originally Posted by
HTeam
Single bank alt - In the same guild as team, receives and sells stuff, organizes bank vault
Enchanter in group - break down that stuff, keep a large enchanting back on this character
Addon - Passloot - I set my enchanter to auto DE everything and everyone else to pass except my main. My main can need an item and pass it to whoever needs it, otherwise it gets disenchanted and bagged easily.
Jamba - use the autosell grey items option
Crafting alts - characters made specifically for each craft. I don't do this in WoW currently, but I've done it in the past in other games. Each character receives and stores items specific to his craft. Using bank tabs or individual bank slots/bags may work here too.
Mostly I like to keep everything either on the character that uses it (#2 is my enchanter, he has all the mats) or keep it in the hands of my bank alt.
Bank alt on each account. While I only use one main bank alt, I have 4 so they can pick things up and mail them to the team on the same account for instant mail.
The minimum size bag you should have is 18, probably 20 (they only cost around 65g on my server).
Additionally, how are you entering dungeons? I'd suggest using the port straight to dungeons from standing next to a vendor who you can sell to. Then you can port out, sell and port back in.