The best approach for Microsoft may be to work with companies like HTC, LG, Motorola (after Lenovo fully takes over) to allow users to back up their Android images and load Windows Phone. The ability to go back to an Android back-up via OneDrive (which is how you pull it off) could make the switch less worrisome.
People buy Android because that's what they're told to buy, but customer satisfaction with Android is very low - crazy low. Satisfaction usually sits at 30% or less. Yet people use the phones everyday and need them, so there is fear and many are hesitant to just jump to Apple.
Microsoft NEEDS to make it easy to move over and they have to find a way to get most apps over. The central problem for many is that they are locked into Gmail and use Google and Youtube frequently, so having no official apps hurts all the Google users and Google is in a position where they don't need to make WP apps. That means Microsoft has to create seamless ways for people to move off Google services (mostly) entirely. There is supposedly a HTML5 Youtube app coming. Truth is that the email client can handle Gmail just fine. Google Drive is not terribly successful, so an opening could be coming.