Well for starters, adding support for all talents would be great since its optimal to change them on specific encounters.
Singletarget most people use HotW+FoN talents, good burst at start with trinketproccs metagem/nature's grace and all 3 treants together with Celestial Allignment then to follow up with using FoN on hastebuffs (nature's grace, legendary metagem-procc) or +intellect proccs from trinkets.
Multitarget people tend to use Incarnation paired with Dream of Cenarius-talent, which gives us 25% more damage while in eclipse, this is gained via using healing touch when at around 60 to a eclipse or in combination with nature's swiftness.
Most of the things above are taken from MMO-C's excellent moonkin guide, which also goes more in-depth on optimal rotation depending on talent-choices etc!
[Moonkin] Guide :: 5.4 Edition