Revision Tips for A-Level Exams?

Hello, guys

I just wanted to ask a few questions because in about 2 weeks! I am starting my first exam which is the BTEC Cambridge Tech IT and then other exams which are on May/June so my first question is: Is it enough time for revision?

2. How long do I have to revise each day to aim for atleast a B, but want to achieve A/Distinction

3. How long do I have to revise for each subject? I am doing:
BTEC Science Level 3 - Unit: 1 - Principles and applications
BTEC IT Cambridge Tech
GCSE English retake
GCSE Maths retake
A Level German

4. Any other revision tips or recommendations?

Thank You