If you are developing an application for Windows Phone 7 and are hoping to get your application published into the marketplace – then you need to read this post!

Straight from the WP7 Marketplace gurus, here are the top things to consider before submitting an application for certification to help increase the chances the application will pass testing the first time.  This list is based on some of the experiences we’ve had working with some of our early adoption partners who are busy building the applications you’ve seen us talk about at some of our Bootcamps and Launch Events.

1) READ the docs!!!  Understand the application policies that represent the requirements all applications need to meet in order to pass certification testing. Here are links for your convenience

• Windows Phone 7 Series UI Design and Interaction Guide [PDF]
  This document is all about the design of your application. Do you have a Pivot Control stacked inside a Panorama Control?  That would be bad.  Are you using the Windows Phone 7 built-in styles to display text and highlights? If not, it could raise some additional questions. PLEASE read this first one thoroughly (it’s a long read) to make sure you understand what METRO is all about, and what the design checkers will be looking for.
• Windows Phone 7 Application Certification Requirements [PDF]
  This document is a short, easy to read explanation of the application certification process and the requirements behind it.  At less than 30 pages, this one is one you also want to start off with because there are some very specific requirements that you’ll have to include in your applications depending on what your application does.  Using the Location Sensor? Do you ask the user if that’s OK to do? Do you have a way to turn it off? Will your application “work” with the Location Sensor turned off?  This is the kind of information in this document and it’s critical that you read it before you submit your application.

2) Know your iconography.

• Test Case 4.6 - Screen shots should encompass the full 480  x 800 dimension, must be a direct capture of the phone screen or emulator and needs to represent the correct aspect ratio.
• Test Case 4.5 – Avoid using the default Windows Mobile icons.
• Including a panorama background image is optional, but recommended. This will enable Microsoft to potentially feature your panorama image on the Marketplace catalog to help improve your application’s visibility with the likely result of more downloads.

3) Support Information – Test Case 5.6.

• Until 10/31/2010, it is recommended that applications include the version number or support information (for example a URL or email), which is easily discoverable by end-users.
• Modify your applications now to help plan for 11/1/2010 when this test case will be enforced.

4) Toast Notification – Test Case 6.2

• There must be the ability for the user to disable toast notification.
• On first use of HttpNotificationChannel.BindtoShellToast method, the application must ask the user for explicit permission to receive a toast notification.

5) Applications Running Under a Locked Screen – Test Case 6.3

• This only applies to applications that continue to execute when running under the locked screen and does not apply to applications in a suspended state.
• Prompt the user for explicit permission to run under a locked screen upon first use of ApplicationIdleDetectionMode.

6) Back Button – Test Case 5.2.4

• Back button behavior is one of the most typical failures.
• A common failure is pressing the back button during application runtime exits the application, instead of returning the application to a previous page or closing the presented menu or dialog.

7) Themes – Test Case 5.1.1. Avoid controls and text washing-out by testing applications with the Theme Background set to “light”.

Languages. Be sure that the application description and the text the application displays to end users is localized appropriately in the target language.

9) Failures upon Upload to the Marketplace. There is a validation tool that assesses your application upon upload to the Marketplace. Some common failures are:

• Error 1029 – Your XAP in missing an interop manifest. Make sure the interop syntax is specified in the manifest file. If the account does not have permissions to run interop, this error message will also be generated.

10) Windows Phone Developer Tools. Be sure to use the RTM version of the Windows Phone Developer Tools as applications built on previous tool versions will fail testing.

• There were some important changes between the two versions, so make sure you re-test your application on the RTM bits to makes sure everything is cool.