I posted this a while ago on Emmerald's forum but it may be useful here as well: -
First, let me say I have no affiliation with the Rawr developers other than being a long-time user of many/most of the modules. I have seen a lot of people who have looked at Rawr but not really worked it all out yet or are using it sub-optimally (not using the optimiser). It is an excellent tool when used properly and this post is aimed at helping people make the most of it.
Download Rawr from http://rawr.codeplex.com
Useful Settings
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(1) Tools => Options => General Settings - I click "buff sources", "Gem Names" & "Item types"
(2) Tools => Edit Gemming Templates - I set it to only show the top gemming template as it is simpler than seeing multiple versions of each item
Setting up your Character
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(1) File => Load Character from Armory
(2) Make sure the "Enforce Gem Requirements" is checked on the "Stats" tab
(3) On the "Buffs" tab, select all the buffs you want - I select all buffs except the Draenei & potions (I usually save it for a health pot)
(4) Change any settings on the "Options" tab - this is different for each model - I usually set a 5 minute fight, but you may want longer.
(5) In the "Comparisons" pane (right hand side), for each slot, left click on the little diamond next to any other items you have that weren't equipped when you imported your character from the armory - there should be a green diamond next to each item you own
(6) Similarly, mark any other enchants you have access too that weren't on your current gear (I normally select the top 1-3 for each slot).
(7) Tools => Edit Gemming Templates - make sure the correct gems are selected - usually it is ok to use the default but for poorly geared alts I often change it to the rare gems. (Doesn't have to be every possible gemming!! Just the fairly common ones)
(8) In the "Comparisons" pane mark any other gems available that you might need that didn't appear in any of the templates. For Feral I make sure I mark the Nightmare Tear, 20ArPen & 10Agi/10Haste gems.
(9) File => Save!!!!
Optmising Your Character
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(1) Tools => Optimise
(2) Select what you want to optimise for - For Feral, I optimise for DPS rating (Selecting overall for feral would include survivability)
(3) Add any additional requirements - You might like to select "Avoided Attacks % < 0" if you want to be hit/expertise capped. I DON'T do this as enforcing the caps may(often) give you a result which has a lower DPS score. Also, for tanks you might like to set "Chance to be crit < 0"
(4) Thoroughness - Time take to optimise varies greatly with which model you are using and how good your PC is (and how many items you have marked). Try an optimise at the default setting to see how long it takes and then adjust this slider accordingly. Greater thoroughness will often give you a better result - I use max thoroughness for my feral and it doesn't take too long - make sure you don't have silly items marked ie. don't have T7 or T8 stuff marked if you have T10 gear - trinkets "may" be an exception as things like Darkmoon Card, ArPen trinkets are OP for their ILvl.
(5) I would suggest ignoring most of the check boxes at this stage. It can be useful to let it pick the best food/flask for you, but I usually leave all these unchecked.
(6) Hit "Optimise" and let Rawr do what it does best!!
Using the Build Upgrade List
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Say you are running 10man regular Icecrown Citadel tonight. You can use the "Filters" in the "Comparison" pane of Rawr to select only the 10 man reg Icecrown loot. Then select the "Slot" dropdown and select "Direct Upgrades". You may think that it is then showing all items that are an upgrade for you in 10 man reg Icecrown but this may not be the case. If your current gear is Hit Capped, then +hit items in the lists will be devalued and may not show as an upgrade. But you may be able to fiddle around with gems/enchants or switch in a piece or two that you have sitting in the bank and find that those items which aren't showing as upgrades may actually be significant upgrades. The "Build Upgrade List" allows Rawr to take all these things into account and show every item that will be an upgrade for you. (Often this will fairly closely match what is show in the comparison pane, but you do get a few suprises).
** A warning: This option takes significantly longer to process so it is important that you are fairly strict with your filter settings to reduce the number of items Rawr has to process. Don't just select Icecrown. Select 10 Man regular Icecrown. Or even better (at the moment) select only "The Lower Spire" & "The Plagueworks". **
(1) Tools => Optimise
(2) Your options remain basically the same as what are discussed under "Optimising Your Character" above
(3) Once again, try on a lower "Thoroughness" setting until you see how fast/slow it is with the options/gear you have selected (I use max on my feral)
(4) Hit "Build Upgrade List"
(5) After it has finished you get a new window with a list of the upgrades. If you hover over each one, then the tooltip shows what combination of gear/gems/enchants give you the best results with the potential upgrade.
I hope that is useful to people and will try and answer any questions.....