To start with, go get a copy of SimulationCraft and download the add-on Pawn (Curse, WoW Interface). Got those? good, now make sure you have SimulationCraft extracted somewhere and good to go, then load in your web browser the World of Warcraft site and pull up your character profile. For the use of this post I'll be using my shaman again Kaltaan.
Now we want to fire up SimulationCraft which will look like the picture to the left.
First thing we are going to do is tell SimulationCraft how to go about siming our character. Under the options tab, on the first set of options we want to change the Iterations to 10000 from the 1000 it defaults to. The main reason for that is we want to get the stat weights for haste, hit, crit and mastery, and if you don't do that it won't return those values.
Now that we have that we want to go under buffs and check anything relevant to our characters, buffs that you know you will have in raids, or just self buffs. For my Shaman, since I'm not raiding now I just have Str and Agil, Attack Power, and Melee Haste checked off. Under Debuffs are basicly the same thing as buffs, just what debuffs either you personally bring or what debuffs will be present with your raid configuration.
The next sub tab we want to look at is scaling, we went to check what stats we want to look for specifically, and for enhancement shamans these are agil, crit, haste, hit, expertise, and mastery, as well as weapon dps and speed. You could sim for attack power, and strength, and maybe even stam, but honestly less your still running pre-cata your not going to come across those stats all that often, and stam will generally just return nothing as long as you aren't taking damage then there is no need, and with health pools in cata, you really shouldn't be in to much danger of death less your doing something wrong.
Now we are going to go to import our character profile, hopefully you still have him pulled up in your web browser. One of the reason I recommended doing that ahead of time is that you can not log into the armory on SimulationCraft for some reason so we want to copy and paste that address in for it now, and then hit the import button. And after a little while we should get a screen that looks like this.
There are a couple lines that we can delete if we wish, but its up to you if you want to or not. Since I'm not siming for raiding atm, I'll generally delete the lines that have to do with using a flask, food, and the two or three lines that have to do with using a potion.
Now we want to hit simulate and go get a coffee or take a walk cause it will take a good 5 mins more or less depending on the speed of your computer to do its thing. Once its done it will spit out a results screen.
Now the results will end up in a file simc_report.html in the windows version and you can just view them in SimulationCraft, but if you want to use any of the links in the report I'm going to suggest you open that file into your browser so that you can use the wowhead link as well as the wowreforge and still have to ability to go back to the report.
Now there are a few things you can do, you can click the wowhead link which will open something like this, which where the gear my shaman can use is, whats better then what I'm currently using etc, and use filters to limit it to the content that you care about. A note about the link it gives you though, is if your a shaman for instance you will see leather items, ignore those, as a shaman you don't want to wear leather, if your a plate wearer you only really want plate. The reason for this is the stat bonus that you get from your armor specialization and you really don't want to wear armor that is not designed for your class. You will get more bang for your buck by wearing armor that is intended for you to use.
The second link is wowreforge, this will help you reforge your gear to the stat weights. There are a couple things to note specificity for enhancement shamans and off-specs. You may have to manually enter the weights as just clicking your off spec on the page will return the default set they have. Also a shaman only requires 541 expertise rating, 451 if your a dwarf. If your a Draenei you only need 1639 hit rating, as opposed to 1742 for anyone else to get the spell hit cap.
After everything's is set you just have hit optimize and then go in game and reforge your gear the way they have it laid out for you.
The last bit on the report is gear weights, clicking that will reveal two lines simular to this.
( Pawn: v1: "kaltaan": MeleeDps=2.9863, Agility=2.1691, HitRating=1.2786, ExpertiseRating=1.0402, MasteryRating=0.9727, CritRating=0.7147, HasteRating=0.5319 )
Thats the line that when your logged into WoW that you will import into pawn to allow you to see upgrades and to help you manually optimize your gear, there will also be one that has 0 hit and 0 exp that can be helpfull and reforging if your already at or above the hit rating needed.
Another note about Enhance Shamans and possible melee in general is the weapon speed for some reason gets lost so I recommend your manually fix the pawn import a bit first by doing this
( Pawn: v1: "Enhance": Dps=2.9863, Speed=73.0125, Agility=2.1691, HitRating=1.2786, ExpertiseRating=1.0402, MasteryRating=0.9727, CritRating=0.7147, HasteRating=0.5319 )
( Pawn: v1: "Enhance nohit": Dps=2.9863, Speed=73.0125, Agility=2.1691, HitRating=0, ExpertiseRating=0, MasteryRating=0.9727, CritRating=0.7147, HasteRating=0.5319 )
The bold area's are what I changed, I removed the Melee part from MeleeDps, and added Speed=*. the value for weapon speed will be in the simcraft report.
Hopefully this helps. Please send me any questions are comments, or like if you like this post.