/sci/ - Science & Math

Programmers on /sci/, how do you improve your programming skills?

I have been doing C# for about 3 years now(web applications, desktop apps) however i still feel that i am average at best. What are some ways that as a programmer i can widen/sharpen my skills?

I was initially interested in other languages and platform like java web development and phone apps, but since most of the time i had to be working on my main project i didn't really have time to explore..

Also general programming thread..