I worked in sales for almost 7 years before finishing college and starting work as a programmer. I sold computers at Radio Shack for a short time, before taking a job selling doors, windows, kitchen cabinets, and appliances at a home improvment center. I was #3 in sales in my region when I worked at Radio Shack, and I sold the crap out of doors when I worked at Menards. In those 7 years I learned a lot about how to sell things to people. I learned how to sell things to people that they didn't need or plan on buying beforehand. All of the things I learned in retail sales can be applied to affiliate marketing!
Buzzwords
I mentioned i was a top salesman selling computers when I worked at Radio Shack. How did I do it? Buzzwords. At that time "IBM Compatible" was a HUGE buzzword in the compter industry (LOL). I used that to my full advantage. At that time, at Radio Shack we sold IBM PC's. In order to sell MASS computers I gave people my standard pitch. Then what sent them over the edge into buy buy buy mode was to use the buzzword. I would tell them "These aren't IBM Compatible computers, they ARE IBM computers". Bam. Cheesy as hell, but it worked like a charm. That sentence made me a lot of money in sales commission. That same idea can be applied to affiliate marketing. Think about your niche, compile a list of buzzwords, and split test your landing pages to find which buzzwords convert to sales.
Incentive
Another important thing in retail sales is incentive. Now I mentioned I sold doors at Menards, but I didn't tell you that sometimes, the store actually LOSES money on a door sale. Now why is this? Why would they sell a product for less than it costs them to buy/make? Incentive, that is why. They can take that $18 pre-hung door that costs them $21 to make and splash it all over their ads in newspapers, on TV and on the radio. That brings people through the doors and onto the sales floor. Now your sales people can sell them the door, but also sell them paint, shims, sandpaper, a knob, nails, stain, and a hammer to install the door with. That is where the profit is!
In affiliate marketing there are incentivized offers. You can use do those, but I am saying to use this form of incentive a different way. Use it to increase your CTR (click through rate) on your PPC ads! The offer you are promoting (ie. the doors, knobs and shim) may not be free, but you can certainly offer your OWN free product (ie. the door) on your landing page in addition to the real product, which is the affiliate offer. That's gold money right there. 
Next time, I will discuss 2 more retail sales concepts that can be used in affiliate marketing. Choice and Brands.
Affiliate Marketing