Welcome to this thread which deals with the damage types the Elementalist can deal and how to increase your potential when dealing raw damage, conditions or critical hits. Of course you can't have everything, e.g. focusing on critical hits by using a lot of Air Magic, traits that augment critical hits and upgrades to equipment that add a "+x% bonus to critical damage", will diminish your ability to build up e.g. strong condition damage.
After going through the following tables and texts, I hope you will have understood the basics and can build your own combinations to enjoy your Guild Wars 2 game play.
There are two degenerating conditions available to the Elementalist: Bleeding and Burning:
As you can see, there are three components to the damage done by Bleeding. As those are multiplied (damage x stacks x time) you can outweigh the fact e.g that you are only half the level of your opponent by doubling the time of the bleed applied. So adding stack and duration can be more vital than having a great base damage.
Also notice that your "Power" attribute does not contribute to your level as well as your weapon damage.
If you take a closer look at the table for "Burning", you will notice that it lacks the ability to stack. You either burn or you don't. What makes this condition dangerous is the high base damage, as its level depended component is eight times as high as in bleeding. Keeping up the burning even a few seconds does much more damage, so preventing foes to e.g. move out of field effects will increase the damage.
Can I increase my base condition damage?
Yes. We have also incorporated those numbers into the tables listed above, when we gave our Elementalist 5 trait points in Earth Magic. Each point in Earth Magic is worth 10 condition damage. With 20 points in Earth Magic, his base damage would increase from 51 for one stack of Bleeding to 81 (which is almost a 60% increase of damage).
Can you decrease the duration of the burning and bleeding conditions?
No. Guild Wars 2 knows only skills, upgrades and traits that increase the duration of the conditions. To "decrease" the duration you have to remove the condition, e.g. by triggering the utility skill "Cleansing Fire".
What does Might do to condition damage?
The Might boon () does increase the condition damage by 5 + 0.375*Level for each stack, so our example Elementalist from the tables listed above would gain 35 condition damage from a single stack of Might.
How does Expertise/Condition Duration change the numbers?
Each point in Fire Magic will increase Expertise by one point, which translates into +1% to the duration of the condition. Lets assume 20 trait points in Fire Magic, the 5 seconds of burning condition would be increased to 6 seconds.
How do modifiers from items change the numbers?
Comparing Condition damage item mods to advancing in level 20 Condition damage = 1 bleed damage
20 Condition damage = 4 burn damage
20 levels = 10 bleed damage
20 levels = 80 burn damage
Since Superior runes (e.g. Rune of the Elementalist add a max. of +57 points to condition damage, the upgrade slots on armour might be better spent on other things, when you compare the numbers to a level gain). As a rule of thumb (as numbers come from community calculation and not official Arena.Net numbers), it "plus to condition damage" should be used in blocks of 20, because less has no effect on bleeding.
What are the best trait lines to pick, when you want to concentrate on condition damage?
As you can see from the explanations and examples in the last paragraphs, Fire Magic and Earth Magic will support a build made to deal heavy condition damage.
You can extrapolate this to other professions as well: All trait lines that increase Expertise and Malice will have the same effect on condition builds than Earth & Fire Magic.