I am an instrumental guitarist and have been writing music for many years. One of the problems I have is keeping my music sounding fresh without repeating myself.
I was wondering what problems you guys have had when writing instrumental music? Also, where do you usually start - melody/riff/chords?
Honestly, it really depends. Sometimes it's a melody, sometimes chords, sometimes just a simple riff.
Also, to keep things sounding fresh, what's worked for me is just take a break, listen to a few different artists/styles, and come back to it later. Later can be a week, a month, or a year. Depending on the amount of time you've got into it, you'll notice these things come in waves.