You can find the monthly return of nifty by using a candlestick chart of one month of Nifty. Yours can be calculated by adding every profit and loss except investing and calculating %age on your capital.
Follow these steps to create a PnL report:
For Trading: Create an Excel sheet in which you mention buy price, strategy, sell price, your profits and Remarks.
For investments: Create a separate mention of your avg. buy price and time along with the quantity and selling details if any.