Hi aspirant,

630 score is brilliant. You are already above the mass of people.

1. Concentrate on the areas you are losing marks in. Focus on them. Work accordingly.

2. Revise a lot. Revision is the key . The more you read something, the more it stays in your mind.

3.Try to read for short time rather than sitting for long hours.

4.Focus mostly on biology. try to score full marks in it.

5. Physics and chemistry, try to focus on formulae based question.

Lastly, dont stress, dont rush. Everything will fall into places, just work harder.

Hope that helps.