First, I look at the avatar or photo of the Tweeter. I want to get an idea of who I am interacting with. No photo, no follow.
Second, I read the Tweeter’s bio. If the bio is interesting and complete, I am much more likely to follow that person than if there is only a URL or a few words that don't really tell me what the person does or enjoys. Since Twitter has shut down their "search by category" feature, the bio is a quick way to see if we share common interests, business goals, location, or area of expertise. Even if they are my competitor, I can learn something from them.
Next, I read through their recent Tweets to find out what type of information the person is offering. Big turn offs: 90 percent of the messages are in reply to someone else and I have no idea what they are talking about. While I appreciate the interaction, I feel like I’m intruding on a private conversation if there are no other types of exchange. Big plus: links to helpful tips, articles, and even products to check out. I want interesting content, not just a URL with no explanation as to what I might find by clicking.
Then, I look at the number of updates and the date of the last Tweet. If the person is not active on Twitter, there's no point in following them.
Some people wonder why I use Twitter.grader.com. This service has similar screening criteria that I use to decide whether or not I want to follow someone. If I am leaning toward clicking the follow button but I'm not sure, I will actually go to the trouble of checking their grade on Twitter. If the Tweeter has a high grade, they are probably someone I want to follow.
Lastly, I check the ratio of followers to following. If a person's Tweets are interesting and helpful, people will follow them in return. If someone is following 1,000 people and only 65 are following them, I suspect they are either a spammer, a newbie, or boring.
So, if you are following me and I'm not following you in return, check the above points and make a few simple changes. Not only am I likely to follow you, so are others!