Exclusive games that are not also on PC and proper advertising of this fact.

I could bring the whole company back by having quality prospects like (the cancelled) Scalebound only on XBOX. And by only on XBOX, I mean ONLY ON XBOX. By giving gamers no choice but to get the game on XBOX and effectively advertising this fact, sales would definitely grow. And if the right exclusive hits, then you could be looking at 360 type numbers.

The OP isn't asking what MS can do to "dominate the industry" or outsell Sony or Nintendo, it says return to 360 sales. So when you say "they tried what you're suggesting with the 360" I'll just ignore the irrelevant rest of it and say thanks for agreeing :)

Xbox has the basics to start with. I would start by increasing the first party studios and having company owned IPs developed (between Xbox and Microsoft there are a lot of IPs to use). Bringback lionsgate and making Rare a true studio again would be a major part of it. Work on bring scalebound back to a active project. The idea would be to build Atleast 12-16 IPs that are the back done of the systems and that you don't need to rush projects while you have enough to release a few "exclusive" titles a year. And have a variety of categories for the IPs.
While you are working on getting the first party studios up and running, make deals to have second party games for the system.

Then once we have enough first studio games, work on getting into a cycle for releasing them
Examples
Group 1 (action/shooters I.e. Halo, gears, mechassault, brute force)
Group 2 (action/adventure I.e. Crackdown, sea of thieves, state of decay)
Group 3 (role playing/strategy I.e fable, lost odyssey, halo wars)
Group 4 (racing/vehicle based I.e. Forza, horizon, crimson skies)
Group 5 (family/kids I.e. Zoo tycoon, ori, max and brotherhood)

Make them the basic groups for the first party studio games and release a few every year.
group 1 & 2 should be able to have 1-2 games a year. Group 3 & 4 should be able to do 1 game a year. Group 5, would be the most mixed group. It would have 3 to 4 releases a year. But all the games don't need to be top AAA titles.
Rare has a lot of titles, that would also be reused and make a line of games, make a line of games called Xbox classics and sell the original in the live store for $7.99?, then make new games with the IPs and sell the. For like $34.99. To help save costs, the games don't need the state of the art graphics, but a good game play and the Xbox classic line would be a huge selling point (a new battletoads, bonkers). At this point you are adding 10-12 exclusive games a year easily and you are covering all the price points (arcade, mid, and AAA titles).
Then add in a few second party games in, and your looking at 12-15 games a year, you can release them throughout the year, so you always releasing exclusive not available on the PS4/Switch.

Next I would add full keyboard/mouse support for the Xbox. Then unite the Xbox/PC store under the Xbox brand. And expand the play anywhere program. Work on getting the indie developers to sell the "play anywhere" and they can be sold for the Xbox/PC market in 1 store. The Keyboard/mouse support will open up more "PC" games to the Xbox system. And have multiplayer available for all the games for PC/Xbox United for people that get the games with "play anywhere". (People would have a choice to pick all players/PC only/Xbox only/controller only in settings for multiplayer).

For the next system (just calling it Xbox). It would be based off a modular system. When you buy the system for a first time, you would get the chassis and all the components. The advantage of the modular system would be say the base system is 4K, but during the next cycle 8K because with new higher option. Instead of needing a new console, a person would be able to just buy the needed modular part, and replace the needed parts. (I know some people wouldn't care for this modular system, but this would but a end to the console cycles for the most part). And the plus side if everything is modular plug in system that would be easy to charge parts, if something goes in your Xbox, you nolonger need to send it in to be fixed or buy a new one to get the higher level. And the biggest advantage is that all games from this point would always work on the Xbox now forever.

No. 1 Avoid another red ring of death debacle at all costs!!

No. 2 Games are art and as powerful a medium as books, films and painting. They have the potential to be better than all those if given the chance. Sony already realise this hence the WIDE spectrum of both AAA and indie games they allow on their console. 

No. 3 The executives behind Xbox CANNOT be accountants and bean counters. They need gamers who are executives. These GEs would be able to spot talented game studios and games and invest in that studio's vision.

No. 4 TV, tv, tv, tv, tv, tv, tv etc should be an after thought if they want to capture true gamers as their core fansbase.

No. 5 They need game developers/stuios who output the kind of game quality that Kojima, FromSoftware, Naughty Dog and Santa Monica Studios do. ND particularly has changed the expectations of gamers in that respect. Combining gameplay and story like almost no other devs. I recently played Horizon Zero Dawn and you'd think GG would have spoken to ND about how to polish their 3rd person shooter, considering ND are pretty much the benchmark now for this genre of game. Don't get me wrong HZD is a good game, but it just doesn't have the finese that a ND title has. And they are part of the same company, so not excuses, other than ego stopping them sharing info/tips to make better games!! So Microsoft need game developers of the ND calibre, regardless of the game type being released on their platform. They need to raise the bar if they want to beat Sony next gen. 

6. Stop with the backwards compatibilty rubbish. If gamers want to play retro games, they should invest in MAME. The Xbox brand should be able innovation and pushing the envelope not a box that plays old games better. Wrong message to prospective buyer, IMO.

Final advice, Don't turn up to the next gen battle with last gen or 2 gens ago weaponary and mentality. Games and gamers have changed!

1) Separate myself from Microsoft.
2) Have sexual relations with my new partner Razer.
3) Help develop a modular based console based on the same concept as Project Christine.
4) Finish a future proof modular console what components can be upgraded on a whim and main truck upgrade as better technology comes out.
5) Invest in first party studios. Each studio capable of trading employees to expand on multiple game genres.
6) VR ready
7) Custom Controller Layout. Analog stick and directional buttons able to rotate on the fly. Keyboard and Mouse support for all games.
8) Free online multiplayer games.
9) Subscription based for discounted products. Includes services for Store/Stream/Download playable games options. One flat subscription fee.
10) Main console component and subcomponents sold separately and bundled. If you don't want the uhd playback you don't have to buy it. Fits more budgets.

Focus on 1 or 2 more exclusives. Ryse was pretty cool Maybe develop that more.

Ori was a masterpiece and thank god theres a part 2!!!!

Add 1 or 2 more great quality titles would be where I start.

Have a look at Sony't press conference yesterday in Paris. If you look at the AAA games announced they covered everything from for the hard core gamer (The Last of Us 2 ) to soft core gamers (Concrete Genie). Their games also covered adult themes like bullying Concrete Genie, child physical abuse in Detroit: Become Human and religious zealotry in the Last of Us 2 trailer. This is what a mature entertainment medium can offer, as well as the classic no thinking and purely fun shoot em up and racing sim etc. Microsoft and Xbox need to start understanding this if they want to be a major player next gen.

Sadly Scalebound would need a major overhaul to cater to more gamers. The last seen "Dude/Bro" angle Scalebound had would grate on most gamers after the first hour.  But I agree that Xbox needs TRUE exclusives, that can't be found anywhere else. Sony got that right for selling their console.