Hi - I have one bit of advice that served me well on the way to getting 48V.
It is not about quantity of questions, it is about quality.
What do I mean by this?
There is little point in doing lots of questions if you don't truly understand each one before moving on. So, do a few questions, see what you get. Then go back over the ones you got wrong, and really get into WHY they are wrong, if you don't understand - ask on here, every question has a thread.
Then, if you are satisfied you know them move on.
Then the key bit, the next morning, do the same questions you did yesterday as a 'warm up' - you saw them yesterday and understood them, so it should take you 10seconds each..
This forces you to understand every single question before moving on. It's also a good confidence booster to set you up the right way for the day ahead.