For English you can start with reading newspapers like TOI, Indian Express, The Hindu daily. This will also help you for current affairs. Buy any good books focusing on the exams you are concenterating. Those will do good with GK part.
Read books of authors from abroad; various countries and stories describing local stuff or historical events.
It will be fun and adventurous to read it
-> you will remember it better thanks the feelings connected
-> you will understand the context of the event, you will see how it is related
-> thanks writers from various cultures, you will see the events from the POV of the author, not from your own (as when you read encyclopaedia)
or for you wikipedia is also good.