1. Be local. Most if not all online business makers consider their business to be international or at least limited to their country. I would recommend in the beginning to think about your online business as the business for your city or your region only. That will make you to concentrate on the things which are really important than to conquer the world.
2. Find 1 customer. In the very beginning think about success from the perspective of finding 1 customer not hundreds. If you find 1 customer in 1 month you will understand how to find 10 customers in one more month. When you find those 10 more customers you will understand how to find 50–100 customers on the third month.
3. One customer can bring Ten. You past customers is the main point of growth. You may feel yourself uncomfortable to use them for references or recommendations. Just make it as gentle as you can but make it.
4. Spend your time instead of money. This is probably the most important and I should put it on the first place. Do everything yourself and spend your time on learning instead of employing someone. Everyone can make a website within 2 weeks with 0 knowledge of programming. Everyone can learn the basics of SEO within 1 week. But those basics will bring you 80% of success.
5. Fail as much as you can. Get used to failure and start enjoying it.