You can start by fixing a timetable where you spend time everyday solving problems related to aptitude questions. If you are preparing for a exam in particular then please mention the same and we may be able to suggest you some of the best materials for that.

Please don't think that It's impossible for you. Rather think positively and prosper.

Also the solution to all your studies related problems is to have dedication and proper concentration.

I understand it becomes really difficult to concentrate on your studies, specially during this time.

Below I will share some tips that will help you to concentrate better:

• Find a time which is best suitable for you to study. Some find it better to concentrate in the morning while others find they can do better in the night.

• Decide what portions you would like to finish in that particular day

• Prepare a timetable according to the above, keeping slots for breaks

• Start studying with your favorite subject, so that you don’t get bored from the beginning itself

• Take breaks when you get bored, and try to avoid studying at a stretch for a longer duration.

• Always keep some time apart for your hobbies, exercise, etc.

• Eat healthy food, sleep well and also socialize. A healthy mind is the most important for good concentration

• Do some mind games like Sudoku, Crossword puzzles, Chess, etc

• Also try meditation

I hope my answer helps. All the very best for your future endeavors!