Composition / Harmony / Progression Theory Help?

Hey all,

I've got a question:

Does anyone have any tips for making variations on themes and altering them so they can progress to make an entire composed piece?

Too many times will I write a theme that sounds good, but I can't do anything with it. I'll come up with a theme, maybe I'll be able to add some 4-part harmony to it, but I can't get anything past that. I'll have this 4-8 measure theme that I have absolutely no idea how to transform to repeat again, so it sounds like it's progressing, modulating, or moving, through a whole piece.

I'll try stuff like inverting it, adding another line over it or something, but it all doesn't fit in. I feel like I've hit a wall.

Does anyone have any tips for this?

Also, does anyone have any good harmony / composition theory books that I could read that would give me an insight on this?

This happens to me often. I don't think the great composers ever said "Oh, here I'm going to invert my melody and add this harmony..." it should come naturally, so try and hear things in your head before you right it down. If you can't think of anything try experimenting with different melodies/harmonies because when you find something that sounds interesting it usually leads to new ideas.

http://www.composition-contest.com/kbase/kb15.htmI have trouble with this as well. Also, sparky, Mozart actually had a method for expanding a short note theme by ten. Maybe this will help you, but I don't understand it: