Have you ever heard of mouseover macros? This is one of the best macro ever, don't wait more !!! use it
A macro consist on selecting an ability, like "Blessing of King", add some additional functions to it, and then use it on your actionbar in place of your non-macroed "Blessing of King" spell.
Let's take some exemples :
/cast [target=mouseover,help][help][target=player] Blessing of Kings
This macro takes the usual "Blessing of Kings" buff, but add a mouseover fonction.
Say you bind this macro to the key 1. When you hover someone with your mouse and press 1, it will buff him without even having to select him with a click. if you have a target but nobody is hovered, it will buff your target, otherwise it'll cast it on yourself.
Now what makes this function even more enjoyable is that it also works on the orginal wow party and raid portraits
as well as every frame UI addon. When raid healing just put your mousepointer over the party member frame (name, picture, hp, mp bars) and press 1 and it will heal him.
note: There's a similar addon called "clique" who let you bind spells on your mouse button, but mouse clicking isn't as accurate as keyboard pressing, particulary if you need to chain your general cooldown, like a protection warrior, or most healers, unless you own a dedicated gamer mouse.
More exemples :
/cast [target=mouseover,help][help][target=player] Flash of Light
cast Flash of light on the target your are mouseovering(works on portrait or body), or cast Flash of light on your selected target if no mouseover, or cast Flash of Light on yourself
Focus the target you mouseover
/cast [target=mouseover][target=target] Hammer of Wrath
Hammer of wrath is the paladin finish move who can be used when the target is bellow 20% health. So using this macro will allow you to finish ennemies in bgs raids etc without having to select them, just mouse pointer on him, press key, dead... Oh did I mention that you were still auto-attacking your selected target at the same time?good stuff huh? ^^
That works for every class, it adds a lot of fun to the gameplay particulary for the healers and tanks, if you have more questions about how to use it, post here.