If the WADS allows direct linking, set that up first. This allows the prospect to go from clicking the ad, directly to the merchant's sales page.
Direct linking is the fast and lazy way to see if an offer converts. If you can get within 20% of breaking even, tweaks to the ad, or creating a lander can make the difference between a campaign being profitable or not.
If the WADS doesn't allow direct linking, you must set up a landing page on your website. It should consist of a headline, photo, subheading, a few bullet points, a couple of paragraphs, and a clear call to action, with an easy to find button.
All the "traditional" marketing tactics can be employed. There's everything I've already shared about creating personas and writing emotionally charged ads. There's Dan Ariely's framing of offers. Plus there's Robert Cialdini's principles of social proof, scarcity, consistency, authority, liking and reciprocity.
The language and tone from ad, to lander, to sales page should match as closely as possible. The color harmonies on the lander should match the sales page. The graphics, photos, headline, bullet points, should all be in harmony.
Keep it simple, with all important data above the fold. That means no scrolling down the page to see the call to action.
The photo can be supplied by the merchant, or it can be a stock photo that you choose. Just be sure that the emotion in the photo is in harmony with the sales page.
The headline can be the same headline from the PPC ad. Without a good one, people won't read the body copy, or bullet points. The photo stops the eye and arouses curiosity. The headline creates desire to read the rest of the page.
The bullet points can be the copy from the PPC ad, with a couple more benefits thrown in. And most importantly, the call to action button must be big and in a contrasting color to the rest of the page.
It shouldn't take more than 30 seconds to read your lander and get the emotional gist, the feeling, the end result this product will bring. If it's longer than that, rework it. You want people to land, get interested and click off to the merchant's sales page. (The exception being review style sites.)
Just do your best to get the lander up quickly. You can fine tune it later. Keep testing and keep improving. Change one element at a time to see if conversion rates go up or down. Keep what works, toss the rest.
If your message is just straight information, think twice. If it doesn’t provoke a reaction, it’s invisible.