Whats next step? Am starting a Dropshipping company in India. I'll start with say 200 to 1000 shirts

I believe this will work here in India since there are more and more people willing to earn extra sitting right at their home. This gives a scope for future in dropshipping business. As am being in textile business, I know where to get shirts at a low cost and as am also experienced in ebay I know what types of shirts will run.

But due to some past action, I have no money left with me. So, i need an investor. How to find and convince an investor about my idea? Also i do not have any business plan currently. Do I really need to have one?

It is very tough for an investor to be your partner by trusting you verbal speech so you must need a well-defined and detailed business plan that is realistic and work-able too. Other than a market research and feasibility report; you should also conduct a risk-analysis to prepare your investor in advance for the possible chances (percentage) of downfall that may occur.

Put simply, the more detailed and realistically-defined your business plan would be; the more number of interested capitalists and their trust you will gain.

Yes you need a business plan - for your own sake as well as to show your investor. If you are serious about making this a great business, you will spend the time it takes to do some strategic planning, to research your market and to improve your idea.

It's not easy to find investors in the current climate, let alone for a business with no revenues (and no business plan)! An investor will most likely be someone you know who is already in the industry. However, they will want to see that you have some skin in the game also (ie. that you have put some $ in.)