7. CUSTOMER SERVICE (thanks to SassySashadoxie and PUREnaturalMinerals who posted similar)
One, make sure you are having fun at this. If it is not fun, then your customer service, attitude, and art will reflect that. Two, treat the customer like how you would want to be treated times 10 or so. Always, go the extra mile. They will appreciate it in more ways than you can know at the time. Three, hand written notes or thank you cards. Four, Communication, communication, communication. Tell them you got their order, when it was shipped, when it is expected to arrive, and thank them for their order as soon as you receive it. This is really important for those first time customers or first time Etsy shoppers. Five, don't stress when you don't have sales. They come when they do. Often, they come in spurts. Enjoy the down time with a little promoting, team building, and working on your art.

8. BALANCE YOUR VENUES (thanks to CharlieandSarah)
Don't count on one source of revenue. Keep your baskets balanced between: Selling Online, Weekly Markets, Large Indie Craft Fairs, Street Fairs, Wholesale, Consignment, Online Drop-shipping Sites, etc.

9. KILL WITH KINDNESS
Every once in a while I get a jerk... "why didn't I get my package, it's been 36 hours since I placed my order" - Or recently a meany on Flickr saying he was going to report me for posting only pictures of my product. What?! So always kill with kindness... be so super polite and helpful that the crappy customer can't help but be satisfied, no matter how much you want to tell them to sod off.

10. ONLINE PROMOTION (thanks to DRyan327)
Ning.com, Twitter.com - Do a 3 day ad on Facebook or Myspace. They are $5.00 a day, and just remember not to let it run too long or you will get nailed for an outrageous sum of money. A lot of the popular blogs have inexpensive ads, some more than others, but here are a few... http://www.craftcult.com or http://www.craftopolis.com. I have a folder on my computer that I keep adding to that has all the good "promotion" type things I have found.

11. THANK YOU GIFT (thanks to Bluebell - I actually do this too)
For some (but not all) of my buyers I will add a small free gift with their purchase. On every order I take one of my mini business cards and punch a hole in it and tie a piece of ribbon on it. On smaller orders I wrap in pretty tissue paper and tie with ribbon.

12. SMILE (thanks to NoneSuchGarden)
If you do shows, SMILE. No matter how tired, hot, cranky, or sore your feet are, act happy to be there and enthusiastic about your craft! So flash you best smile and work it!

13. CONFIDENCE
When approaching a store to display your paintings, plan an opening party, or maybe sell your jewelry wholesale, exude confidence and experience whether you feel it or not. Walk into that salon with a portfolio of beautiful pictures, head held high shoulders back like you've got your work on the walls of Parliament, much less a little boutique. Confidence makes a WORLD of difference and also makes that store owner more confident to work with YOU since they now see how capable and businesslike you are.