*Sits in Armchair CEO*
First of all, I'd start showing more confidence within my own OS and ecosystem by showing either Priority by releasing the apps FIRST....and not make my users wait for months or even a year or so for the same app OR i'd release them all at the same time or within the same time frame with feature parity.
Secondly, i'd realize that I have a great gold mine of a feature like Xbox Live and stop making it so difficult for those who WANT to actually develop for my platform and bring games to my users who want things like achievements.
Thirdly, I would not wait an entire year before releasing a phone.....if necessary, I'd simply release a mildly upgraded Lumia 1525 for Carriers like T-Mobile, Sprint and Verizon OR Bring the Icon to the other carriers. Or even bring high end stuff to Canada....If I see people are clamoring, I am not going to expect my users to wait a year because that's a risk that could very well blow up in my face.
Fourth, I'd stop releasing Low end after Low end device with little to no differentiation between the two. If I was going to bring out a 535 later...then why even waste time with a 530. Just make the actual 630-635 the 530 and bring out the 535 as the 630/635.
Instead, let's confuse users....and if rumors pan out, let's confuse em even more by adding MORE options like a Lumia 430.
OR hey...let's release a phone like the 830 but price it too high for what it offers and gimp it on the FFC but let's throw that amazing FFC into the 730/735 and yet gimp it on the back camera. Why not simply merge the two into the perfect Mid range/selfie phone...there's little differentiation between the two.
Fifth, I'd realize that while my marketshare is not high and at times slipping, that perhaps annoying my loyal users by degrading the experience(I.e. Xbox Music) and then saying wait till Windows 10 is not the way to go about retaining loyalty.
Or releasing that despite breaking things like Hubs from the OS, it actually hasn't really helped the APPgate that much. I'd realize that simply following trends and trying to be like Google/Android is not the way to go about it because I am only alienating my userbase by ignoring their wants....They don't want yet another low end or midrange. They want a Lumia flagship...
I'd realize that I need to stop following trends because the thing about trends is...THEY CHANGE instantly....and I'd adapt to trends while using them to my advantage and making my experience unique. With all the money that Microsoft throws around, enter into a contractual agreement with these developers or get Rudy to actually make the apps. If they don't want to make it, then at least try and pay them for access. You may not be able to do it for every app but do it for the big apps...6snap(Snapchat), 6sec(Vine), 6tag(Instagram/FB), 6tin(Tinder). Pay them for access if they don't want to do it themselves.
Sixth, market my devices.......and actually showcase them and make creative ads....not some random commercial. More Commercials like the Lumia 1020 commercials.
That's 6 things I'd do
And Luckily for me, I actually do have a very tiny voice within Microsoft and I use it daily