First of all, 68% isnt even that bad!?
Can you still do well?
No, you can't do well if you keep thinking of the 68%! Forget about it, drink a glass of water and forget it ever happened. Start fresh, one sac out of ~5 makes such a minuscule difference to your study score. So, do not worry about it, you made a mistake but you learnt from it, so ultimately you should be glad you didn't do as well!
Study tips:
Well, I haven't even done methods yet nor obtained my study score, but from my sac results I think I have a reason to share my tips. First of all, as above stated, you need to forget about that 68% or else it will haunt you and crush your goals whenever you think about them. This is a fresh start, you are starting a new topic now so shift your focus fully this topic. I think if you really put your head to it, and devote hard work, time and consistency to your study in methods you can definitely improve your grades drastically. It will obviously be hard in the beginning stages, but if you persist, trust me, you will reap the rewards! So, remember that it's not about 'how many hours' you study, but for maths, it's about the quality of your study!
Head up, and don't let one setback get you down! Keep fighting for that A+!
- Cosine