1. Know the important chapters
2. Refer to NCERT Book
3. Solve previous years papers
4. You can visit topperlearning.com for NEET Crash course
Part 1: Factual Biology: Four chapters of diversity in living world, three chapters of structural organization in plants and animals, cell: unit of life, human health and disease (except Immunity portion), evolution (evidence and brief account of evolution), strategies for enhancement in food production and microbes in human welfare.
Part 2: Conceptual biology chapter units: Biomolecules, cell cycle and cell division, plant physiology, human physiology, reproduction, genetics and evolution (mechanisms of evolution), biotechnology and ecology
So, you have to be thorough with all the chapters