What type of products do you sell? Do you only sell local? Nationwide? Global?
I use google adwords it works great
if you have website you need to target that area for keywords such as _____ _______ San Diego, California.
Second, you can write articles about the products (if you are in sales) but even if you are in plumbing industry you can write articles about your home prevention tips for san diego home owners.
If you need to know where to submit those articles, you can check out this article..
The marketplace where you need to take in order to understand that you need to this.
An easy question to do.
An experienced professional that understands your goals what works for one business even if they are similar in nature finding an experienced professional that understands your needs and sitting.