Can someone coach me in decision making?

Im silver 2 (almost s1) i was gold in preseason. Been playing since end of season 2 and have about 5000 ranked games (most of them mid) i main mid i particularly like the assassins. I feel the main thing holding me back is decision making. When it comes to knowledge of champs and mechanics i seem to have that down. Anyone have tips on how to make better decisions in my games?