DON'T throw it in a bag and slap the address on it. THIS IS NOT EBAY!
That brings me to my second point. Always, and I mean Always, include a free gift. This is another way to make your customer feel special and appreciated, and is also a very nice way to thank them for shopping with you.
Check out my other Etsy Guides:
The Three Most Common Etsy Mistakes
Photography on Etsy: Inanimate objects