I'm not studying biomed, but I'm studying science so hopefully some of my advice may help you.
For me, I find that studying is important, but what is just as important is having a healthy lifestyle conducive to successful study.
What do I mean by this?
Sleep
It may sound clichéd, but going to bed at a reasonable time makes a massive difference to how you perform at uni. I have an alarm set at 9:30 each night to remind me that I need to get off of screens and do something relaxing like reading before I go to bed at 10. Aim to get up early at about 7 each morning and you will feel more motivated as your brain has had adequate rest and you won't get that feeling when you wake up at 12 and realise half the day is already gone. Keep it consistent on the weekdays and try not to stay up too late on the weekends.
Food
It can be so easy sometimes to just skip lunch or breakfast because you don't feel bothered, don't have enough time or money etc. Don't give in to it; make sure you're eating at least 3 decent meals a day so your mind and body has the energy to study and you're not distracted by nagging hunger. Include plenty of fruit. Some people like caffeine, others don't - I find that some days I just need that extra push so I drink a coffee but caffeinating yourself everyday can be counterproductive.
Free time
Uni is stressful for all of us. We have exams coming up, assignments due, papers to write, lectures to catch up on etc. Don't get so caught up in your studies that you leave no time for yourself. Have other interests outside of uni and dedicate an amount of time each day to just doing stuff that you find fun. It can be anything, as long as you enjoy it. For me it's watching YouTube. If you don't commit to leisure, you will burnout and drift through a state of sadness and lack of productivity. There's threads here about this if you want to learn more. Essentially, just keep that work-fun balance.
Your environment
If your room is a mess it can drain your motivation, at least for me it does. Try and keep your room as clean as possible and limit potential distractions. Coming home to a clean room after a long day is always so much nicer than coming home to a clutter. It can be difficult to study at home because of how easy it is to just ditch the books, get up and watch some tv. So either force yourself to return to study or go to your local library or uni to get it done.The next time you consider giving in to a distraction, just ask yourself, 'do you really want to waste your time doing x when studying is so much more important? What will be the consequences of not studying now?'. My uni has excellent facilities dedicated to studying and I find myself focusing on what's important a lot more often when I'm at them.
In terms of study methods, there are two that I find to be very efficient and beneficial in learning.
Firstly, answering questions is an excellent method. You think you know all there is to know about a topic and then suddenly a question throws you off. Once answered, you learn to see the theory/concept from a new perspective or you discover an important nuance. As an added bonus, this prepares you very well for assessment.
Secondly, teaching; this is by far the most effective method. You know that one friend that is always struggling? Help them out by explaining the key ideas in your own words. If they ask a question and you have no answer, note it down and research it until you have one. If teaching friends isn't an option, teach your pencil. Yes this really works. As ridiculous as it may seem, this is going to force you to organise the information in your head into a presentable standard - a standard required for assessment. It also reveals gaps in your knowledge. "x does this because y, and y does this because... ummm..." - There's your gap, now go gather more information so you can really nail your explanation! You will really understand whatever it is you're explaining on a deep level if you follow this advice. I wish I knew this in year 12.
As for actually learning the content, I don't know if there is a best method per se. What works for me doesn't always work for others. I learn best by watching videos, others learn best by reading for example. It really depends on you. I'm sure you would have figured out by now what you prefer but you could still experiment with other learning methods.
You said that you don't have a game plan yet. I'd recommend getting in a routine. It mitigates stress and saves time as you know what you're going to do, and when you're going to do it, as opposed to everything being messy, chaotic and unorganised. Routine ensures you have enough time to do all that you need to, and if you stick to it, pretty much guarantees you will accomplish those things. Set one up that is compatible with your current lifestyle and one that isn't so strict that you won't follow it long term.
These are the main points that came to my head, sorry I didn't have any tips specifically biomed related. Hopefully you can make up for that mid sem mark by smashing your next assessment! Good luck!