Organic chemistry has to be practised daily. First, concentrate on all the basics and types of functional groups and other must know things. Next practise one functional group at a time.

Some tips you can also follow:

• List all the name reactions on a chart paper, and hung it on the wall where you study,and just read them anytime you are free.
• Practice conversions.
• Learn distinguishing tests.
• Understand imp concepts of +I,-I effects,resonance effect etc.
• Practice previous years question papers.

Good Luck!

You can go through below tips -

Learn About Structure
Build a Strong Foundation

Work the Problems

Prepare Mind Maps

Don’t Forget Acid-Base Reactions

Focus on Understanding, Not Memorization

Use Study Partners for Homework & Tests

Hope this helps!!!