The most important thing I've learned so far in about 10 days of playing 6 max is that the world will not crumble if you don't stick to a strict guideline for preflop hands. In a lot of games I will open raise QTo/66 or better depending on how I've been playing. If I've been playing a lot of hands lately or I've been getting played back at a lot even when I raise from early position then I stick to slightly better hands.

Then some simple stuff is that if I'm first into a pot I come in raising.

As for AXo, it still isn't a good hand. Depending on the game I may open with AX from CO if I think it can win me the blinds, but at 1/2 this doesn't happen a ton. Opening from button/sb I come in raising.

About slowplaying big pairs, I think it's pretty stupid. In the past week the only time I've "slowplayed" a big pair was one time with AA on the button when they had been folding to my button raise the past few orbits and another time from the BB when the button opened. In a heads up pot it's not that bad, but it's probably better to just put the bets in while you have the best hand. In multiway pots slowplaying is obviously horrible.

Ace high most certainly can have showdown value in shorthanded games. In fact, against certain players you can actually value bet Ace high with good kicker to get called by a worse kicker (or by retards that call down with J high). You're going to be showing down a lot more marginal hands.

I think the most important thing #2 I've learned so far that I can suggest is: get good at value betting.

I went from playing 2/4 full to 1/2 6 max and I'm pissed at myself that I didn't switch to shorthanded earlier. You get way more hands per hour, plus you get to play a lot of hands you'd never play in full games. Playing 4 tables I'm almost always involved in a hand, unlike full where I'm usually sitting and waiting forever.