check out the forums, all over it you can find helpful things that will help with promoting a business to even starting one
The basic premise that I'm TRYING to live by is that PR is better than spending money on ads - not always the case - but if you have a product you can publicize this works.
It really depends on type of business. In general try to build links as much as you can. Then in a one or two months search engines will start sending you traffic.
Get you name known - how you do this is up to you, choose from links, merchandise and make sure you get repeat visitors. PPC is good if you get repeat custom also. Also if you are really good - word of mouth is the key. Hope this helps...