First thing. Go lighter. Were the last few set supposed to be push presses? If so you need more legs. If not you need no legs. The Legs should not get the bar started on a strict OHP, if they are it is too heavy.
As far as technique goes let’s start with the rack position. Your elbows need to be up and out in front of you more when you start. Start by shrugging the weight up and driving with the elbows, not dropping the elbows and leaning back.
Also have you watched any or all of THIS yet?
If not you should.
