I learned mostly by discussing hands with other players. It helps to really open your mind up to things that you might have previously considered to be standard.

I talked a lot of strategy with Hokie and Dboy (hu limit guy now) as I moved from the $5s to 100s.  However, I talked the most strategy with a friend who got me into poker back in early 2007.  He mostly played 6-max but he loved studying and reading about the game even more than playing it.  He was a 2p2 junkie back then, reading all the strategy forums worth reading and got me into the heads up forum.  That's where I ended up meeting Dboy (hand history exchange) and Hokie as well.  We used to sit on ventrillo during sessions, sometimes railing each other when one of us was tilted or during breaks.  I can't say it helped improve our games at a much faster pace than if we all took it super seriously, woke up at 8am and studied hands and did HH swaps on 2p2 constantly, but the most important thing is that it was fun and kept us interested while improving and playing.

Otherwise, just debating facets of the game with others has helped a lot, keeping an open mind to every part of my game, any decision I face, that is really the key.  A year or so ago I couldn't fathom a lot of the plays that I regularly make as even being an option.  Realizing that exploitation of your opponent can require extreme adaptation is huge, and that sometimes your extreme adapting will lead to some really weird plays that are actually the best play vs your given opponent in your specific situation; that is big to me.

I moved up at a much faster pace.  I also had (and have) another primary source of income, so poker was basically an investment and I didn't cashout for at least 1 year from when I started, when I was already in the $115 turbos.

I moved up when comfortable, which was 20-30 buyins.  I generally took some shots at 20 buyins and would move down if I lost 2-5 buyins.

I started in the $5s, then tried $11 turbos, I went from around $200-250 bankroll and dropped 5 or so buyins over 83 games and went back into the $5 regular speeds.  Then I moved into the $10 regular speeds, and kept taking unsuccessful small shots into the $20s when my roll was around $400-500.

On the advice of dboy, I moved to the $11 turbos again and things really started clicking.  I almost never bluffed back then, basically just positional play and full value betting.  I mixed in some 3-bet bluffs by default, which in hindsight was a slight leak at the time (I believe it lowers your winrate and heightens variance against the typical 3-bet calling station opponents in the lower levels).

My results varied as I moved up, but were always winning.  I didn't stick around any level too long, not long enough to build a reliable sample.  My most successful stake was a 24% ROI in the $33 turbos for a little over 200 games, and I moved into the $55 turbos for around 100 games and quickly moved into the $115s, where a lot of my leaks started to catch up to me.  I probably struggled with a 1-3% ROI there for 1k-1500 games before finally getting to 5%+ ROI two tabling.  I hadn't 2 tabled until I reached the $115s.

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To summarize, I basically moved up when I felt comfortable and made sure I had 20-30 buyins.  Once I hit the $115s I stuck with them even with 30-40+ buyins.  I still sat fish at higher levels, particularly $200 regular speeds, but it took me awhile to take a full $230 shot.

As long as I reminded myself that I could always move down, taking a jump to the next level was not really a huge deal, except initially.  I was a little hesitant on my first move up or two after the first ~5 buyin loss in the $11 turbos, but once I got back into the turbos and started moving up, I really was not worried at all about any jump.  As long as you're comfortable with what you are risking and are comfortable moving back down, you should not be worried about taking a shot.  Best case, you play and run well and stay at the stake, worst case you lose a few buyins and move down.

I play both now, but I tend to burnout faster in the regular speeds when I run bad.  There's something about running bad for 30-45 minute matches that forces me to quit sessions sooner than if I play turbos and run bad for 10-20 minutes in a game.

For me, running bad often leads to me playing bad after awhile, so I just quit when I recognize that it is likely to happen (quit means I take a break anywhere from 30 minutes to being done for the day).

As for turbos and regular speeds, it's up to you.  I still play both these days, and the tilt factor isn't too common if I'm multi tabling the games, but the regular speeds in the $100-200 level are usually clogged up on Stars (where I play most often) so turbos represent an open table more often allowing a high % of bad players to sit me.  I find that regular speed opponents tend to be worse players on average (lower stakes, worse negative ROIs) but I end up double sitting regulars too often for me to prefer those games over turbos.

In the low stakes, you can develop your game and skills in either structure.  The regular speeds should mean slightly less variance to your game, as your ROI should be higher in those games, but as you continue to improve your play you should be a good winner in both formats.  Go with what works for you, they are both very profitable.