Keep it simple, keep it short, and build a habit.
This is the shortest writing-advice column you’re ever going to read. But this is the advice I always give to aspiring writers when I teach at a writing conference:
Write 10 minutes today. Then 10 minutes tomorrow. Don’t make any excuses about this because everyone has 10 minutes they waste each day. Focus for 10 minutes and 10 minutes only.
Do this for 30 days until you have a writing habit.