Not an affiliate anymore, but one thing I always maintained – and I think all savvy affiliates will agree – is that you need to know your traffic.
I’m not just talking about men – women ratio or other vague demographics, I mean things you can use like what banners pull clicks (by that you can see what interests your customers), where those banners are on your page and which sponsor converts your traffic.
Success to me = money. once you have studied your site trends, you should know how much each link to a sponsor program is worth per click. Then you test new offers to see if you can increase it.
Traffic tips are always good, but I think people tend to forget that more traffic does not always mean you will make more sales. Optimizing your outbound links does.
Changing a link color to blue to increase clickthru’s 
man that’s old school! I think if you want to generate more clicks affiliates need to be using marketing text instead of generic “click here” – people know to click on something when the cursor changes.
Join link exchanges. If you are just starting out, there is no better way to get a ton of back links (and even some traffic).
Just my 2cents.