Further Training

I think my musical skills are beginning to plateu, despite my technical skills continueing to increase.

I've never taken any musical training before, what musical training is good for furthering composition?

I was concidering piano lessons but i only have a 61 key controller?

i would sugest for you to go buy yourself a digital piano heres one that probaly about $500 u.s.

casio cdp-100 - has 5 sounds = grand piano 1, grand piano 2, elect piano, harpsichord, strings

learn theory, and like dillinger escape plan, once mastered throw what u have learned out the window n make music...