<-- Father of two boys, 9 and 5.
Consistancy... If you aren't consistant, then he/she can't be consistant.
Pick your battles... Don't rag on the kid for every little thing. Eventually he/she will figure out that it's impossible to please you, and give up.
Be accountable... If you give an ultimatim (i.e. "Pick up your toys and then you can stay up 30 mins." or "Pick up your toys, or you're going to bed early."), you'd better stick with it. It's not negotiable, once you've laid down the ground rules. This kind of goes along with consistancy. And if you promise them something, you'd better hold up your end of the deal.
Treat them with respect... Sounds like a no-brainer, but I see crappy parents all to often who talk down to their kids, as if they aren't worth the effort to carry on a civil conversation.
Balance negative and positive reinforcement... If he/she deserves praise, be sure to mention it.
Btw, I think asking kids what makes a good parent has the potential to be very bad advice. When I was a teen, I thought I knew it all... But now that I have kids, I realize that I didn't know sh*t.