I’ve been wrestling with this issue. Over my first year I have mainly been focussing on what I am naturally good at, and enjoy doing, but with rather mixed results in terms of sales. I’m going to try adapting myself more to the requirements of stock music (I think I still tend to think too much in terms of producing a complete ‘song’ structure with a verse, chorus, middle 8 etc., rather than something that works well as background) but still sticking to genres that I’m comfortable working in.