Hey.

You can use the following tips for improving your retention capactity.

• Read thoroughly and try to understand what you read.
• Make notes for each topics. Give headings and subheadings in your answer which will help you to retain each point better.
• Use flowcharts to  important concepts 
• You can use memory tools like mnemonics etc which makes retention easier.
• Revise your notes
• Fix a schedule accordingly for making notes as well as for revision.

Best of luck!