2- make sure that the .xap file name is the same name you used in the submission process.
3- Text boxes and text blocks are not visible in light theme of windows phone by default you should change their properties (you can check the light theme on the emulator settings).
4- Never use brands,logos and trade marks in your icons or part of it that will cause your app to fail the tests.
5- The language in the assemply info should be the same language selected in the submission process (note that: “English” is not equal to “English US” or “English International”)
6- Try to prevent your app from crash, by using “try-catch”.