1. to know your target customers, the demographics of a certain location can help you pick what type of business is really needed
2. your location must be surrounded with a lot of people
3. budget- i think it'll be better to start with a small capital then if its a success you can gradually make your business bigger (low risk)
4. you must have a unique concept-- a selling point

and although its not necessary, open a business where there are fewer rivals