Well, if it's used well it can be a really good marketing tool. I'm far from an expert on the subject, but here's my top 5 tips anyway!
1. Be a person
People buy from people. It's important to come across as a real person and not just an automated selling machine. Use your own language, be informal and most importantly be yourself. You should mirror your real life personality online. It's less of a shock if people actually meet you!
2. Don't be an egg
This is an extension of Number 1. Get yourself a profile picture. I always wonder why people don't have an avatar. Are they shy, embarrassed or just lazy?? Get one! I prefer photos but as a minimum at least get your logo up there.
3. Follow the right people
Firstly there's a chance they might follow you back. But more importantly you can pick up tips and tricks from the people who do it well. Follow your competition and people in the same business in different parts of the country as well. You'll get a good feel for the latest trends in your industry and get some ideas for new products and offers.
Don't just sell! Comment on other people's tweets. Reply to messages. And always say thank you when someone follows you. And you can be a bit interesting with what you tweet as well. OK, no-one cares what you had for breakfast, but other stuff might be interesting. Have you won a new contract, had a good afternoon at a local attraction or at the beach?
5. Time it right
If you have an important message to get out make sure people will read it! Around 9am and 5pm are peak times, but for a more accurate measure you can use sites like 14Blocks to see when your followers are on line. If it's not convenient to tweet at those times you can always use sites like HootSuite and BufferApp.
Hope that's useful to some of you. I'm no expert but these tips work for me... And if you fancy following, I'm @ChrisLynnPhoto