I was curious as to how other people are studying. For example, I'm mostly doing a few medium and easy one's every day or so. However, some of the hard/medium one's are nearly impossible for me to wrap my head around. Is it okay to look at the answer? Sometimes I look at the solutions, and still don't understand wtf they are saying! Can anyone relate to this sentiment? Also, how do you know when to move on from easy questions to medium/hard questions?

Do you have any videos or tutorials you are using to study?