When it comes to choosing an appropriate coding project it's your motivation to code that has the greatest influence. It's the project which dictates the programming languages and coding skills you'll need.
For mobile app development it's the target platform (iOS, Android, etc) and development framework (Appcelerator, PhoneGap, etc) which will dictate your learning path. Of course, you'll also need a good app idea.
A rather different approach is required for open source or community projects. Here you'll have to look around to find a project that interests you. Then scan the associated task list to identify the items you wish to work on.
Regardless of your final choice it's important to have patience and realistic expectations. Thinking you'll be able to construct a complete website in a few hours, or build an app in a couple of days, will only lead to disappointment.
Make It FunRegardless of your motivation or project coding should always be fun. One approach is to consider the development process as a sort of game. Here's a few ideas:
Split tasks into levels. Ensure the initial levels are easy wins and leave all the ambitious stuff to the end.
Keep score. Keep a note of your coding progress. It's always encouraging to look back on past achievements when the going gets a little tough, such as during a tricky debugging session.
Reward yourself. Identify a reward for each level, say a foody treat or a special drink at your local cafe. And maybe a software/hardware purchase at the end of a successful project.