You must have a good, well laid out and you must put a lot of effort into it. Failing at this step could greatly impact your probability of success. In this video I go over landing pages that I believe to be bad, better, and great! This will give you a great understanding of what type of landing pages are used for CPA.
If you are good at developing landing pages, there are virtually an unlimited number things that you can do to make your pages unique. One point that I stress in this video is that custom landing pages are the way to go. You want something people have never seen before so they'll be more likely to complete your offer instead of someone else's.