This pic and subtitle from an excellent blog of writing advice:

http://www.whimsydark.com/blog/2016/12/14/your-writing-questions-answered-how-do-you-find-your-voice

Kristin Shields writes it – and that particular entry is full of practical, good advice about finding your writing voice.  To put it simply, write lots, be genuinely yourself and read widely the words of others – and allow time for it to develop – as long as you’re writing during that time, not just twiddling your thumbs.