How to reach +2200 in bullet?

Unfortunately the answer is really boring: it takes a lot of work. There's no secret shortcut.

900 rating points is a lot.

Ok, if you're serious, then you're going to have to learn a lot about chess, and play a lot of slow games. Do a lot of analysis. Preferably play in OTB tournaments, read books, that sort of thing.

Then, after you've learned a lot, after your OTB rating is getting close to 2200 (lets say at least 1900), then it's the easy part... now you play bullet for a few hours a day, every day. If your OTB is around 1900 then you will probably need some tricks like a special opening repertoire and it might take a few years of playing bullet regularly to do it, but it's definitely possible.

If your OTB rating is closer to 2200, then it might only take a few months of playing bullet every day to get there.

If you've been playing bullet for fun while getting a 2200 OTB rating, then you'll probably already be there.

Well, it's different for everyone, but a realistic estimate is it would take you 4 or 5 years.

If you have no job, or you obsess with chess and work over 4 hours a day on chess, then maybe a lot faster than that.

If you play and analyze 100 otb longchessgames a year you will earn enough chessknowledge to be able to play intuitively , safe, agressive and fast . The best bulletplayers are they who are best in longchess. Magnus Carlsen and Hikaru Nakamura are fantastic, and all the GMs are good at bullet.

Preggo answered very good

It has taken me about 2 years to go from a bullet rating of 800 to 2200 (although my current peak rating is currently 2217 and my actual rating is probably somewhere in the low 2100s). The first step in that was getting my OTB rating to around 1700 after which I had enough chess knowledge to get my bullet rating to about 1800. I was helped by the fact that my main strength is how quickly I see moves and especially early on that assisted me hugely. After that I attempted to become a better blitz player (went from 1600-about 1950-2000) so that I wouldn't get blown off the board by stronger players. I also worked on my opening repertoire although compared to most players of my rating it is still quite limited. Essentially I tried to cut blunders out of my game and learnt how not to lose. After this blitz phase I went back to bullet and was able to win more games on time and achieve more draws and wins in even positions and as a result my rating went up to about 2100. My next goal is to hit 2300 and I don't feel that I'm too far off it.

Get a really good internet connection

My friend @Monasa did it. Bullet is largely intuition and pattern recognition; play solid openings that you know well and try to exploit any tactical opportunity you can. Tactical openings like Sicilian are fine if you know them well but assume that your opponents will know it better than you. Even though I'm a Sicilian player against e4, a solid opening like French or Caro-Kann may be better for bullet. Of course I'm currently only 1900 bullet but I too hope to achieve 2200+ sometime.

As for secret tips: Hovering, Premoving, and getting better at time scrambles / converting endgames seem to help the most. Also focus on not blundering and take any loose pieces your opponent may drop. EASIER SAID THAN DONE! ;D