There are many different traffic generation techniques. If you're going to really sit down and make a list of the different techniques, you'll probably come up with more than ten different types easily. You list could look something like: Adwords, Yahoo Search Marketing, Adbrite, Article Marketing, Forum signatures, and more.
The key to choosing the appropriate traffic source depends on your business goals. If you want quick traffic just to test out some offers you have, or if you simply want to get some conversion stats for your landing pages, then you may want to consider buying traffic from the major search engines. This is the quickest traffic source and will often give you insight into how strong your offer is. You can decide how you want to scale up your business afterwards once you have some numbers. If you can't convert with quality traffic, then you probably need to go back to the drawing board and rework the offer a little bit more. Then test it out again.
Once you're satisfied with the conversion results, here's where it gets exciting. Remember that when you're testing small, you're only getting a trickle stream of traffic from one single source. Now, if you're going to scale up your business, you should be looking at the different traffic sources. Not all traffic sources will give you the same numbers, so you have to be diligent and track all your traffic sources. You can do this by setting up different landing pages for different traffic source.
One of the most reliable traffic source that I've tested so far, and has worked well for me and many other successful internet marketers, is article marketing. Unlike buying clicks, article marketing usually starts off slow. That's because article writing and submission takes time. And some article directories take up to weeks to approve an article. Then the search engines take their fair share of time indexing the pages. This whole process could take up to weeks before you see traffic coming from the different sites.
However, the good news is, once the links are indexed in the search engines, you have a traffic source set up for good. It'll cost you a one-time effort to write and submit the articles, but it'll reap rewards for you many times over, making article marketing one of the most reliable and profitable traffic generation method.
Take a good look at your traffic list again, and consider your long term strategy. Buying clicks is a good way of getting traffic very quickly, but bids can go really high and if you're not careful, you could burn a big hole in your pocket. Besides, once the advertising stops, the traffic stops as well. So whatever traffic generation methods you're comfortable with right now, find some time to really look into article marketing. I can assure you that it's going to be well worth your time.