USE THOSE TOOLS
One key way of making sure you get other people to follow you on these sites is to use the tools they give you to promote your social networking status elsewhere.
For example, Twitter has a range of badges or widgets that you can use elsewhere. These are ideal for putting on your blog for instance, and they even have ones that have been specifically designed to go on Twitter and Facebook.
They’re worth using because they enable you to attract more followers from outside the social networking sites. Once they find you, they are more likely to follow you – especially if you make it easy for them by using widgets like these.
But there is another tactic you should use as well if you are going to join more than one site. Whatever you do, make sure you link them all together. It seems to be assumed that if someone is on one social networking site, they will frequent others as well. So don’t be shy about promoting your other social networking efforts; in fact, you will find that some sites give you space to put your screen names for those in as well.