How to crack DI?

I never have prepared or dedicated a good amount of time for the DI section solely. I thought if I'm good with QA & VA I'll be good with DI too. Maybe this is the mistake. In my full length mocks my DI score ranges 77-80. Time management is one of the biggest issue I acknowledge that but that is due to lack of practice. How do you guys prepare for DI? I don't find many sectional practice questions. To reach my target I wanna get 85+ on DI. Need your suggestions.