How do you select your sets in DILR? I am having a problem in selecting the right sets.

I am good with LR except for truth teller and complex mathematical algebraic puzzels so i do them last first i select the easy ones that are there. I know the easy ones because i know which questions i get stuck at and which questions i am able to do and i know these because of practice.So, look at the sets you have solved see what you are good at and try selecting them first,but if they are very hard in cat leave them and do the easy ones.