If you just want to get started on something and see results quickly I recommend making use of an external API so you don't need to have users before it works.

If you just want to get started on something and see results quickly I recommend making use of an external API so you don't need to have users before it works. For example, use Google maps and some other source of location data (Tweets, Foursquare venues, etc) and mash them together. This will give you plenty of problems to solve and code to write but will also give you results quickly and keep you interested. Note: I don't recommend building your real app to be reliant on 3rd party API data but its a great way to get a small project started. Note 2: Regarding ideas to implement, I'm sure someone in your immediate circle of friends complains about something to do with their job so try to fix it. It is actually quite hard to make a useful and usable app to help out people. Hint: it can be ugly as hell as long as it does something useful.