Title says it all: How to improve post flop OOP with wide ranges?

Received some coaching, clearly I mess up postflop OOP with wide ranges. BB vs CO is bad, BB vs BTN is bad, both in 3bet pots as single raised pots. Pre flop I am too tight and post flop as well. How to improve this? Like my bb winrate is terrible, apparently calling ranges are decent, after that stuff goes bad.