Creating High Performing Silverlight Applications for Windows Phone が公開されています。
上記URLよりDownloadが可能です。
以下、Overviewのみ本文より引用して紹介します。
Compared to a desktop or laptop PC, a Windows Phone 7 device has a more limited amount of CPU and GPU (graphics processing unit) power. To make Silverlight run well on a Windows Phone 7 device, many changes have been made to the Silverlight graphics engine and other parts of the platform. This download includes a document and samples that illustrate tools, tips, and examples that you can use to make a Silverlight for Windows Phone application run faster and be more responsive.