With your mocks, I would advise you to treat them like your real exams and put in a lot of effort. This will stand you in great stead for next year as you’ll have a much better understanding of the course. It will also help to build up your self-discipline and work ethic.
I would make yourself a plan each week with exactly whet you’re going to revise and for how long. Not just ‘biology’ but ‘biology unit 1 cells from 5.30-6.30’. It’s up to you how long you revise for but you should try to push yourself outside your comfort zone and build up disciplined habits. I’d do at least 3 hours on a school night and then 6 hours on Saturday and Sunday in the month before mocks.
I also think it’s important to hold yourself accountable or get someone to do this for you. Review honestly at the end of each week whether or not you have followed your plan and reward or punish yourself accordingly. Rewards could be things like watching a movie on Netflix. Punishments could be thins like making up double the time you’ve missed the following week or no phone for a day.