Strategies
You've done your research. You know optimization is something you need to be doing. Now, where do you start? Which campaign? Which pages? How do you sell it internally?
Start with pages that clearly drive the greatest proportion of sales, sign-ups or other primary business objectives. For most advertisers and companies, landing pages linked to a specific PPC or display campaign are a good place to start. You'll get the biggest bang for the buck and effort with bigger campaigns in terms of media spend.
Related sales funnels also can have a huge impact. Many companies have a multi-step sales process which can include forms, shopping carts, and other pages. If one of these pages is poorly designed, or if pages work poorly together, it can negatively impact the entire process.
Keep in mind that optimization is not a one-time project. You need to develop a culture of continuous improvement. Only by pursuing cycle after cycle of testing and optimization can you reach the world-class performance levels achieved by leading web properties.
Test, optimize, learn. Rinse and repeat cycle.