There are so many people out there who have a Twitter account, or want to set one up, but have no idea how to successfully use it to get followers or sell your product.
The first thing you have to keep in mind is that Twitter was made for social networking. Not for advertising or selling products. The most simple way to put it would be saying to take your Myspace or Facebook page, and take away EVERY part of it except the "status update" section. You have 140 characters to say something of interest. That's less characters than you have for a text message!
Many people use programs (google) 'twitter tools' in order to mass follow and unfollow people. While they seem successful in gaining followers, I wouldn't recommend this personally. How many of those people are actually interested in your product?
How do you find people to follow?
If you sell on Etsy, there are many threads in the forums you can search for 'twitter' in order to find some people who probably will follow you back. Start a thread under the "promotions" section. Add your link to your business cards. Put a notice up on your myspace or facebook with a link. Many people do "link love" on their facebook pages where they'll let you add your own links onto their pages. These are the easiest ways.
There is also a search option on twitter you can use to your advantage. Type in a term relating to your product and do a search to find others tweeting about it. If you sell baked goods, search for terms like 'cook' or 'recipe'. If you make your own clothing, try searching for 'fashion' or 'shopping'. Pick some relative words and see what you can find.
Most others WILL look to see who is following them, and look at your page. How do you get them to follow you back and stick around? SAY SOMETHING INTERESTING!!!
We all want to promote our shops as much as possible. But nothing is more annoying than looking at a page and seeing nothing but updates that say "I just listed ____!", and seeing that repeat. If I see someone updates their status more times in a day than can fit on one page, I probably won't follow them.
Vary your tweets. Sure, post one about that new necklace you just finished and put up on Artfire for sale. The next tweet could be a nifty quote you found that particular day. Maybe a random odd thought you had. Something interesting you may be doing. Others like to see a real person behind the profile, not just someone trying to sell-sell-sell.
@someone else. If you see someone on your page post something, find a few to click! Mention them! Typing the @ symbol before their name or using the "reply" button on their post you can look at their link, and maybe say "hey thats a cool ___ you just listed!" or "I just checked your shop out and fell in LOVE with ___".. Interact with your followers. Interact with others who don't sell also. Don't overdo it, but making conversation or commenting on someone else will have them sticking around a bit longer.
Stick your shop URL in your profile section under settings/more info URL. That way everyone who views your page can see it and click, without it screaming at them in each post. You can change your background to be a photo of one(or many) of your products. Add a picture of yourself or your product. I personally prefer seeing one of the person behind the profile. You're letting others see a real person.
When you get a new follower, please don't make the mistake of sending them a direct message or anything saying "Hey thank you for the follow! Come look at my shop!". If they're following you, chances are they have already checked out your profile as well as any links on it.
On the right hand side there are options. If you start to follow enough people you can add "lists". That way you can separate your real life friends from others with shops to whatever else you'd like to add. I personally like viewing tweets this way, and use 'friends' 'read daily' 'bath and body' 'cloth/clothing/knit', as well as many others. The link listed @___(insert your username here) will lead you to the page where you can see others who mentioned you in their tweets. If someone else has, acknowledge them and say thanks! You can 'favorite' others tweets you may want to come back to, and there's a section to view and send direct messages to others.
Since this is long enough I'll stop here and my next installment will be on how to use certain other twitter tools from different websites to your advantage.