Whenever I try to create something artistic and start but get stuck in the middle my mind tends to wander.  At first I will be trying to find ideas to advance the project but I then begin to think of other art-ish things that have little or no relation to the project I am currently working on (like going from writing a poem to thinking of musical riffs).  I understand this isn't necessarily a bad thing, but it becomes a problem when I need to get a project done (I am a student).  Any advice you can give about this?
try much shorter projects first, they are much easier to finish, and you will get some practice and hone in on your process. then when you are ready you can move to longer projects, and you will complete them handily because you will know what you're doing by that time