Organic Chemistry makes up a massive portion of A Level Chemistry (9701). The biggest hurdle is the synthesis questions: 'How do you get from a primary alcohol to a nitrile?'
The Master Mind Map
You cannot memorize reactions in isolation. You must build a giant mind map. Start with Alkanes in the center. Draw arrows to Haloalkanes, then to Alcohols, then to Aldehydes/Ketones, and Carboxylic Acids. For every arrow, write the Reagents (e.g., K2Cr2O7) and Conditions (e.g., reflux, acidic, heat).
Active Recall on Blank Paper
Every week, take a blank sheet of paper and try to draw the entire mind map from memory. Check it against your master copy. Highlight the arrows you missed in red.
Mechanisms are Free Marks
Nucleophilic substitution, electrophilic addition... these mechanisms are guaranteed to appear. Practice drawing the curly arrows until you can do it in your sleep. Remember, the arrow always starts from the lone pair or the bond, never from the atom itself!