Your best bet would be to not compete at all. That doesn’t mean that you shouldn’t make your product if you truly believe it can be successful, but know that neither Xitter/Facebook make any actual money from their social media services. Xitter has never been profitable and Facebook only makes money from their malvertising. Instead, try to find a dedicated userbase and build your app around their needs in a way that is first-and-foremost sustainable as a business.