Hello vyuhitha,

Venkateshwarlu book is easy to understand and also easy to grasp structures , vol 1 and vol 2 surender nath Pandey , sanjay k Pandey , and william foye is more detailed and good .
In terms  of preparation first start with practicing the drugs classification then practice simple drug structure and mechanism of actions ,
Then  synthesis process then structural activity  relationships,

Follow an organised manner in writing the structures , don't panic as those will seem difficult in starting but keep on practicing everyday to get command on subject ,

After all preparations , you will get some important points in William foyes book which will be helpful for you for quick review as well ,

Medicinal chemistry is more understandable when you are perfect in pharmacology and pathophysiology ,
Then medicinal chemistry will be cake walk for you ,

I wish you good luck dear ,

All the best for your preparation ,

Thank you !