Preflop Basics

[hockey1]

Sorry in advance for such a basic post, but I'm a successful middle limit (15/30, 30/60) full game player who's just starting to play shorthanded (Party's 6-max 5/10 and 10/20). I'm pretty comfortable with my postflop play, but I'm a little unsure of "standard" / default preflop play for these shorthanded games. Any guidance would be appreciated, in particular in the following situations:

1. A7o in middle position. What about LP after a limper or two? What about button after a raise? SB to a raise?

2. ATo button after a raise. ATs? What if there's a raise AND a cold call before it gets to you?

2. QJo from EP/MP

3. 89s first in from CO.

Any rules of thumb (e.g., is it correct to raise virtually any A if first in?) would also be helpful.