I seem to be going through the game world ass backward; to help others avoid this fate, here are things I've learned. Please add to the thread!
Disclaimer: Things I wish I had done may be things you'll wish you hadn't done. I didn't do them, so I can't tell.
* Sell old gear. An NPC tells you to salvage it, but unless you're a mad crafter or auctioneer you probably want to sell it to a vendor to raise the ~10g for your mount.
* Right click on decorative items. They go into an invisible crate in the sky, and stop cluttering your inventory.
* There are two level 6-10 quest hubs. The northernmost end of the low level zones are lowest level, increasing as you move south. Sorry, I don't know where the free taxi is that gets you to the second low level quest hub.