Ok let's run through some of the hunter's main abilities with some quick notes. These abilities should be on your bars other aren't that important. In alphabetical order:
Your main aspect to keep up almost at all times! just pure ap bonus.
Very usefull aspect that basically allows the hunter to never go out of mana, especially when used on multiple targets. In case of single target just do steady shots to regain mana.NEVER apply a serpent sting while this aspect is active, it will decrease your dps on serpent sting dots and chimera shots.
Usefull aspect when the raid is taking a lot of nature damage, you can be asked to put this aspect up by raidlead.
Use this ability when you expecting some big hits, keep in mind you can't dps during this so i suggest to make a macro with a cancelaura in it as well. Combined with Distracting Shot you can save the raid when the tank needs to be ressed. This is the spell to use when raidlead calls to 'pop defensives'
Oooh this is maybe THE most fun ability and yet also VERY usefull. Mastery of this skill will be your graduation marker for a pro hunter! Disengage to move left right back and forward, practice the jump mid-air turn disengage to quickly get to anywhere. Combined with nitro boots you can really get from one side of the room to the other. when mastered you will use this skill alot and love it forever!
Too many hunter's neglect this ability, this is a raid-saving shot when used correctly! it enables you to pull an add from a healer or when a tank is down and needs a few secs to get ressed. It is up to the hunter's skill if it will be a sacrifice or a heroic save while staying alive. Think about Distracting shot>Concussive shot>deterrence>disengage>missdirect to pet>nitro boots>feign death.
After that you can let the tank taunt it again or repeat a bit of kiting to save your pet.
Allthough trapping is more a SV spec thing, this trap will do really nice damage on trashmobs, max your aoe dps combining this with volley. Be sure to have Feign Death ready because your dps will generate agro on mobs.
Dump that agro! Instant agro dump ability and you should allways use this to keep your threat low or to save your ass.
A trap you can shoot, how nice. This can be used as a good way to cc some adds or mindcontroled people. On lady deathwhisper 25hc you can place this trap near a shaman so that he can stand on it before dominate mind and gets an insta cc (so he can save his bloodlust/heroism) can also save a healer who is being attacked by an add.
Trap you should use to kite. good ways to use it is combined with explosive trap on suppresors @valithria and mainly required on LK fights to slow valks and spirits.
I'm going to be simple about this, there should ALLWAYS be a hunter's mark on the target you are attacking! if you have lower geared hunters in the raid you can ask if the have the improved version, keep in mind to not remove their better mark.
Another neglected ability, use this to remove slows etc from yourself but also from tank/heal with a macro.
Another way to dump some agro but a pro hunter will use it to benefit the tank more then for his self interest. start the fight with it to help the tank get agro and make sure you burst during the 4 seconds! keep using it during the fight especially when the tank has issues controlling agro.
Haste bonus you can activate and with talents the cooldown is reduced to 3 minutes. Use this skill start of the fight to allign procs with this haste. I will get more in depth with this abilty in the rotation page.
One of the MM spec gems! This ability will reset cooldowns and if used correctly it can be a huge increase in your gameplay and dps, again i will get more in depth with this skill on the rotation page.
Make sure you allways track accordingly, almost everything in ICC is undead, it is why i used this one as image.
Help your tanks out a bit, tranq those enraged mobs/bosses. especially usefull and expected on LK shambling horrors. I suggest to make a mouseover macro specifically for this fight phase 1.
Another MM gem! Simple.. ALLWAYS have this active!!
Not the best way to replenish mana but i still mention it here because on some fights you can use it nicely when you switch targets.