Here's one traffic tip that I learned recently. And this is the next best thing to being listed on the front page for the keyword that you want. And it's cheaper than PPC too.
Here's how you do it ...
First you Google the keyword that you want. If you are selling an ebook on losing weight, you can type in the word "lose weight" in Google right now. You know how expensive that keyword is with Adwords, right?
I am not really sure but I know that it's expensive.
So the next best thing that you can do is to advertise at the websites in the search engine results for that specific keyword. You may want to negotiate a small investment first, and see how the traffic is converting.
And if the website has Adsense, you can try to look for that phrase "Advertise on this site". And here's a trick if you are going with the "Advertise on this site"
What you can do is have an ad that also calls out the name of that website. I found this website here when I typed in lose weight:
So your ad can be something like:
I Love SoYouWanna.com
Lose weight at my site.com
If there's no "Advertise on this site", you can look for a link that says "Advertise" or "Advertisement", or anything like that.
And you can't find that either, and you are a portal or content site, you can even find their contact details and ask them about advertising rates.
Here's another tip ... rather than asking them their rates, you can straight away suggest a rate that you are comfortable with ... say maybe $1.50 per CPM (thousand impressions). You can say that you want to try out the first 10,000 impression before committing to a huge investment.
By the end of day, check how much traffic you are really getting, and how many sales you get. And then compare that if you were to bid for that keyword in Adwords or Overture in the first place ...