No doubt it is not an easy task.
What worked for me was to follow the study plan (I was with ProPilot).
Read every chapter and made notes on it.
Then practiced questions on the chapter only. I did that for every chapter until finished the books and continued with the question bank.
Went through each question twice. Flagged the ones I was not doing good and then practiced on the flagged questions only.
If I could not remember something or understand it, I used the OAA ATPL CBT ( great learning tool) and tried to find on the internet various publications, videos, etc.
Keep up the good work and do not forget it is just a challenge!
Regards,