The standard issue Moonkin focuses on a lot of the same attributes other casters favor - especially spell power. They are unique, however, in that haste only really helps one spell used in their rotation: The very long-to-cast Starfire. The rest of your DPS spells are instant or very quick to cast (Moonfire, Insect Swarm, and Wrath). Moonkins need plenty of critical strike rating to keep their mana up and their Eclipse cycle going, so it's definitely an important stat to look for on gear. You'll need hit rating too, of course, but thanks to Improved Faerie Fire and Balance of Power, you can get away with a lot less than other casters.
So, how do you "make it happen" as a Moonkin? Well, theres this talent called Eclipse... Basically you're going to want to cast Wrath until you "proc" a Starfire buff, then cast Starfire until you "proc" a Wrath buff, and keep going back and forth until the boss or your group is dead. You're going to want to try and sneak in your DOT's during breaks in your rotation to keep them running, as they provide other benefits interacting with your Idol and set bonuses to boost your DPS "sky high".
The problem with this is that these rotations take a while to get going, and if you don't get "lucky" with your crits your dps can really suffer. Fights with high mobility are in general a problem for casters, but it really hurts a Moonkin to finally land his Eclipse buff and then have to run and waste it. Moonkins are very dependent on getting their Eclipse cycle going to be able to dish out comparable DPS.
As far as AOE goes for trash and heroics and such, there's a few talents you can use to boost your output here - namely, Gale Winds and Typhoon. Grab those and just spam Hurricane on every pack until dead or you're OOM (Hurricane is one of the few spells that can actually make a Moonkin run out of mana in a hurry).
Need some help with a cookie cutter talent build? Try this one.

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It leaves you a few points to play with that you'll place in either mana regen, single target damage, or AOE, depending on your tastes and situations.