You can gamify the experience using the natural human desire to accomplish things and compete with others. Here's what you can do here:
Show leaderboards, scores, and badges
Use wizards that promote a sequence of in-app goals
Unlock some pleasant perks as users achieve these goals
Automatically give your users significant progress credit upfront. People are much more likely to complete something that's already done by 60%. This initial 60% can consist of something as simple as “Log in, register, and input your name.”