I am a UI Developer with 6 years of experience. I have been working in AngularJS for more than 1 year. But still I don't feel I am good in Angular. Since our backend developers mostly work in services, factories and HTTP requests, I mostly work on creating Directives and UI interactions.

So, I need to know what kind of hobby projects will make me a Master in AngularJS. I am eager to use lots of HTTP requests, promises and all. If you are gonna tell me to use APIs, what free APIs will be helpful in learning AngularJS HTTP Services? And what kind of projects will use all these techniques.

Can you please give your suggestions on this? (Note : I am in intermediate level in JavaScript and I don't know much about backend development)