Great apps make social sharing easy and seamless. They make sharing an effortless part of how the app works so that users don't even need to think about it.
Here are some suggestions that will help you design an app that eliminates obstacles and doubts that users might have about using your app and sharing it with friends.
1) Offer one-click facebook and twitter login. This one's pretty obvious. Facebook login, for example, does three things. It simplifies the login process, it enables the app to capture additional useful information about the user and it reduces initial user registration time.
2) Motivate users on the first screen to get started by clearly showing how they can grow their network and start sharing.
3) Prioritize what is on the screen, and show top actions right in view. Users need to know what they can do.
4) Enable users to easily post to multiple social platforms with just one tap.
5) Always make sharing part of the creation process.