You can refer different books from what you generally follow. Keith Williams + Oxford is a very good combination. You can also google or you tube or discuss in a public forum when you come across problems that you don't understand.
I can totally understand your situation. I think most of us are dealing with the same thing. Personally i will suggest you to self study... as they say - self study is the best study ( but what ever works for you. I don't know of any good classes in Delhi. Most of them have made it a money making business).
Watch motivational videos and read inspirational quotes for the spark and start that you are looking for. It always works for me.
Hope it helps. Good Luck.