Generally, 10th CBSE science comprises physics, chemistry, and Biology. Here are the most useful tips for you to score 10 CGPA in Science.

• Practice every exercise of NCERT. Take a colored pencil or pen, and make tiny notes in the blank side given on every page of NCERT books. Underline the important topics. If possible, use colorful pens in doing the same.
• Go through NCERT books from cover to cover and do regular practice with question papers. Here are the sample model question papers for your practice.
  • Most Important Model Question paper - Download here
• Apart from NCERT books, get books of Dhanpat Rai publications (Fundamentals of science), if possible. They're good and explanatory.
• Practicing the diagrams of biology, Equations of Chemistry and  Ray diagrams in Optics are very important.
• Evaluate yourself with chapter wise tests and keep on practicing to improve the scores. Click to download a sample question paper. 
  • Chemical Reaction and Equation repeated questions                        - Download here
  • Magnetic Effects most important model question paper                    -  Download here
  • The Human Eye and The Colorful World  important question paper - Download here
• Buy a chapter-wise question bank that includes previous year questions. Get sample question papers at https://www.qb365.in/materials. It helps you to take more and more practice and complete revision.