Display a Picture of Yourself
In this modern era, there is the increase of robotic Twitter accounts spamming tweets which we all don't like. Providing a picture of yourself as your profile pic ensures all your followers and those that happen to land on your profile page you are a real human and not some stupid robot. This will increase the chance of people following you.
Go for the Head shot!
There will be some Xbox or PS3 enthusiast that will see that as a 'bullet shot to the head' but that is not what I mean. Although having a full body picture will let Twurfers (Twitter surfers) see all of you, it will be more difficult to see your head especially how small the profile pictures are restricted at. You do most of your talking out of your mouth (and I hope not out of your backside!) and as tweets are like you talking, show a picture of your head! This will make followers feel more connected to you like they are having a conversation decreasing the number of followers unfollowing you.
I have heard people of following others on the mere fact that they like their Twitter profile pic. As strange as it is, it's true. Happy positive pictures of you smiling will encourage people to follow more as they subconsciously think your tweets are going to be all happy and merry too. So make sure to say cheese to the camera!
Make it Simple!
Pictures which are quite complicated having many different colours, backgrounds, objects or people in them will lose the focus off of you making the connection between you and your followers be lost. Take one of my profile pictures which is present in this article. The colours are fairly similar with only three colours present: brown, white and green. The brown and colour of the wall help as they match my skin colour. I also have only one person in the picture centring the focus on me. As well as that, the way in which I'm looking into the distance gives the impression I'm thinking in a positive way, making Twurfers think my tweets will in future be positive tweets.
Don't Change it Frequently Another problem you will face is having the 'perfect profile picture'. There is no such thing and because of that, you will most likely keep changing it to find the 'perfect picture' for your Twitter account. This is a big mistake as although it is still you in the picture, your followers will get confused when they see different pictures of you on their timeline. Sticking to one profile picture creates an image of yourself among Twitter. So don't change it!