How can a new guy get into dev?

[Logan]

Hello all
I am a 2nd year cs major, I am interested in linux development and i am 
wondering what the best way to get my foot in the door so to speak. I 
have knowledge of java, a little C and C# and good knowledge of python. 
but my experience seems to be in the educational side of the language, 
like how to make arrays and exercises like data structures. I would like 
to develop for xfce. can anyone offer tips, development environments, 
languages to learn, even  how to get started. i get the dev mailing list 
in digest mode.