HAVE CAPITAL BACKUP. Like, if you have $20 to put into the business, make sure you have that or more as backup. Because if you are going to be buying stock, you will still need to cover your basic expenses like lights and water and rent etc. And then you will have to pay for your stock on top of your running expenses.
(Yes, I've done this before, and I did it the wrong way and I learnt my lesson.)

Write a business plan is the first step. Have at least
6 months backup $$ in reserve. Then wait for a while until the economy improves. A lot of small business people are struggling to make it at this time.

opening a business under an lLC it protects your personal assets and i have ann LLC and i was frustrated till i hired legal assistants to help me with forming an LLC at fbnusa.com
try it or call them 310-455-6675

Competition - similar businesses

Availability - in your area

Market - do you have a sellable product

Costing - to set up

Profit - will it be viable

Advertising ,Marketing - selling your product