The most important aspect is getting past the disappointment of a bad grade and planning your next move.
You need to give yourself time to process. It’s about finding the right strategy, improving your time management.
Work on your gaps. You won’t get better grades if you don’t try.
Talk to your teacher about extra credit. Talk to them about taking on an extra assignment that would help raise your grade, it never hurts to ask.
Establish a plan, it will make it all easier.
Identify your weaknesses, I often make mistakes and heavily lose marks due to negligence.
You have to try and be motivated.