You should attempt only those questions in which you have confidence.

To improve your performance make sure your concepts are clear. Build your basics strong you can take help of NCERT books. If your concepts are clear you can easily solve all types of questions even tricky questions.

Practice as much as you can can. Focus on the important topics. Solve MCQs as much as you can. Do proper analysis of the papers which you are solving. Work on your time management. Know your strength and weakness. So, you can work upon them.

You should refer previous year papers to know the exam pattern and level of questions.

All the Best!!