Not sure whether you have started since your post is 6 months old.
The most important aspect for a start-up is to have a business plan, a reasonable amount of capital to launch.
Since you have been a team lead in a BPO for 3 years, you may already know the operational aspects of the business. However, that alone is not sufficient.
Start asking questions like how did my company manage to get the business from the client on the process that I am working on. Apply reason and you will come to see the importance of many other factors besides the aspect of operations.
5th June 2016 From India, Chennai