It’s an all too familiar scenario. You’ve built the ultimate PPC campaign for a site, but the traffic simply isn’t converting.

Days spent labouring over keyword research. Hours spent crafting dozens of ads to test in the wild. Perhaps you even use a few of your tell-no-one AdWords tricks. But the all-singing, all-dancing site is doing little or nothing to make users buy or sign-up.

Rock-steady advice on how to improve conversion rate is hard to find. Here’s my roundup of must-read material on the subject:

• 101 Easy Ways to Use Google’s New Website Optimizer (Conversion-Rate-Experts.com)
• Google Conversion University
• Free Conversion Tactics Strategy Guide (Mind Valley Labs)
• Mind Valley Labs blog >> Conversion Rates
• 7 Rules for Landing Page Optimization
• “We Tried That Already” (Clickz)
• How Adjectives Can Kill Your Conversion Rate (Conversion Chronicles)
• Grok Dot Com on Conversion Rates
• How Much Has Free Shipping Affected Your Conversion? (WebmasterWorld)
• Increasing Conversion Rate: Your Tips (WebmasterWorld)
• Increasing Your Conversion Rate (WebmasterWorld)
• The Art of the Sign Up Page

Tools like Google’s Website Optimizer and Crazy Egg make split tests super-simple, so no excuses - make a (very late) new year’s resolution to split test everything.