This post is Day #27 in a series called the 31 Days of Windows Phone.

Yesterday, I shared with you a way to share your application with other Windows Phone developers.  Today is going to be a discussion about sharing your application with the world: through the marketplace.

There’s plenty to cover, so let’s get started.

1. Read the Documentation

Before doing anything else, you’re going to want to read the documentation about submitting your application to the Windows Phone Marketplace (also known as the App Hub.)

There are three documents you specifically should focus on:

1. App Hub Developer Registration Walkthrough – a great introduction to getting registered as a developer.  You need to do this in order to submit applications to the marketplace, as well as deploy your applications to actual devices when you’re testing your app.
2. Windows Phone 7 Application Submission Walkthrough – this walkthrough almost trumped the entire purpose of today’s article.  It walks you through each step of uploading your application, and what kinds of resources you’ll need along the way.  You’ll want to gather all of your resources (icons, descriptions, XAP, etc.) before starting the submission process.
3. Windows Phone 7 Application Certification Requirements – a 27-page PDF that outlines what you can and can’t do in a Windows Phone application.  Most of it is pretty common sense, but it’s a quick read, so make sure your application qualifies before you even start building it.  You’ve got no reason to be upset if your application is denied for going against this document.

2. Know How Your App Will Be Tested

Each segment of the PDF above (Application Certification Requirements) is a test case for your application.  Hopefully, you’ve already read the entire document.  If you haven’t, go open it up.  This section outlines some of the “gotchas” you might encounter.

Test Case 4.5 – Windows Phone Marketplace Iconography
Avoid using the default Windows Mobile icons.  This is a new platform.  Treat it that way.

Test Case 4.6 – Application Screenshot
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. DO NOT “enhance” your screenshots.  Show your application as-is.

Test Case 5.1.1 – Multiple Devices Support
Avoid controls and text “washing-out” by testing applications with the Theme Background set to “light”. We covered this on Day #5: System Theming.

Test Case 5.2.4 – Use of Back Button
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.

Test Case 5.6 – Technical Support Information
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.

Test Case 6.2 – Push Notifications Application
There must be the ability for the user to disable toast notification.  Also, on first use of HttpNotificationChannel.BindtoShellToast method, the application must ask the user for explicit permission to receive a toast notification.

Test Case 6.3 – Applications Running Under a Locked Screen
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.   You MUST prompt the user for explicit permission to run under a locked screen upon first use of ApplicationIdleDetectionMode.

Some Other Tips Not Associated With A Specific Test

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.

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

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

3. Icons Are Probably the Most Important Thing

Here’s two quick screenshots from my Zune software.  You’ll notice that as I am browsing new applications for my phone, all I get is a name, an icon, and a price.  (Click it to see them enlarged).

Even though the apps are ordered by “top selling”, you might find a similar order if you sorted them by icon quality.  Your icon is that storied “first impression,” and if you don’t make a good one, you’re also not going to make a sale.

Take some time (or some money), and really make sure that your icon looks professional.  A bad icon brings up a host of other questions about your application:

1. “If the icon is ugly, what does the application look like?”
2. “If they didn’t care to make their icon look nice, how well could their application work?”
3. “This icon looks like a child made it.  A child probably made the app too.”

As it turns out, the Expression team has put together a great tutorial on creating your own icons for the Marketplace.  Check it out here:

http://expression.microsoft.com/en-us/gg317447.aspx?ocid=msexp-fb

4. Build Yourself a Presence Outside the Marketplace

Sure, you’ve followed the rules, created a great icon, and gotten approved in the marketplace.  To make yourself look like a legitimate software company, you should put together a small website above and beyond what you’ve done for your application.  It should provide ways for your users to contact you, and should DEFINITELY let users know what other applications you’ve created as well.  Here’s my example site (though none of my applications have even been submitted to the marketplace yet):

http://blankensoft.com

You can put together just a simple page, but you should have a web presence.  You can get incredibly cheap hosting just about anywhere, and a domain name will run you about $10 a year.  (If you’re looking for hosting, I can’t recommend CrystalTechenough.  I’ve been hosting with them for almost 10 years now.)

If you’re looking for a place where you can get hosting and a domain name on the cheap, check out GoDaddy.com.  Your $10/year will get you email addresses, simple web hosting, and your domain name.

5. Look For Design Resources

There are tons of great websites that you can find fonts, icons, color schemes, etc. for your applications.  I’ve compiled a solid list of them here on this site, but look around.  The appearance of your application and icons is going to have a HUGE impact on your application’s success.  Here’s a link to my list of Windows Phone Developer Resources:

http://jeffblankenburg.com/wp7

Well, that’s it!  Get your application ready, and get it in the App Hub.  It’s time to start making money!

Tomorrow, I’m going to show you another way to make money, through ads on your application.  Until then, make sure you read those documents I linked to at the beginning of this article.