Brian has some basic advice that you should try to follow first. If you are still doing poorly after the fact, it's nothing to be embarassed about since story scaling will pit you against equal skill mobs almost all the time. I remember having a hard time with my story as well from the point where I was trying to find my parents.
Using skills effectively is half of the battle. Although dagger/dagger didn't work out for you, I recommend trying dagger/focus. This combo has two things going for it:
- Conditions that help you kite your opponent and reduce their damage.
- Mobility and speed of skill use that allows you to stay on your toes. No channeling skills for 5 seconds like staff.
The key to getting the most out of any weapon combo is to switch elements after using skills that have longer cooldowns. These long cooldown skills are typically on your 3-5 keys. Your 1 and 2 key skills, although on low cooldown, don't prevent your opponent from damaging you, which is not going to help you survive. Also, although they can be spammed they typically do low damage, so you end up mashing your 1 key for very little gain (the plinking). By switching elements frequently you ensure that you always have a high value ability to use; while playing around with another element all of your previously used skills are burning through their cooldowns. Elementalists are blessed with lots to do while a particular skill is on cooldown (20 weapon skills versus the average 10) - take advantage of it.
Note that this combo really only applies to solo. In dungeons and group events you can't really serve an up-front role as an elementalist - you will find more success staying back and supporting with staff or scepter, given the massive AoE damage and slow heals. Once you have mastered some dagger combos you can get up close and personal in big events.
To give you an idea of how you can skill cycle, here is a summary of my cycle for dagger/focus:
- Lightning, 4/5, 2, 3
- Fire, 4, 5, 3, 2
- Water, 3, 5, 4, 2
- Earth, 1/2 (spam), 4/5 (situational)
Start with lightning. If you are fighting ranged mobs, you can lay down Swirling Winds (4 key) to keep ranged attacks at bay while you lay out your damage. If you are fighting a melee mob, you can start with Gale (5 key) to knock them down while you lay out damage. Alternatively, do damage then knock them down just before they land a blow. Use Shocking Aura (3 key) as well in case they end up hitting you.
Then start to cycle. Switch to fire and burst as you shouldn't be needing water or earth for survivability this early into the fight. Drop a Flamewall and Fire Shield (4 and 5 keys) before doing anything else to start doing damage over time, ensuring you keep the mob in the AoE by standing near it. Then burst by dashing through them with Burning Speed (3 key) and turn around for a Drake's breath (2 key).
Switch to water next as some conditions on your opponent are wearing off. Chill them with Frozen Burst, drop a Comet, then Chill again with Freezing Gust (3, 5, and 4 keys) before using Cone of Cold (2 key). This is a stage where you can lay damage from a distance if staying close is getting you into trouble, as you should be able to kite while they are chilled.
Switch to earth and begin impaling. This is a filler element while you wait for your other cooldowns to finish, because earth does good damage over time that will last long after you switch elements. Now is the time to remove any conditions that you have accumulated using Magnetic Wave (4 key), and if you get into real trouble use Obsidian Flesh (5 key) to go invulnerable for a short time. If you are very good with timing magnetic wave against a ranger-type mob, you can do lots of damage by countering a ranged attack.
If something doesn't fit this cycle then use whatever element will help you the most. Fire is for high finishing damage. Water is for kiting. Lightning is for reducing their attack effectiveness. Earth is for tanking.
Also note that the order of skills while using one element doesn't matter that much: the point is I always have some condition on my opponent while using heavy damage skills.
Your other skill slots (6-0) are also very important. The 6 key is always a decent heal that you should use while you aren't in the thick of things. Remember that if it wouldn't overheal you, now is the time to use it as you want to burn through the cooldown asap before you really need it again.
I also highly recommend Mist Form. While in Mist Form, you are totally invulnerable (although you don't break cc) and you are capable of casting your heal at the same time (6 key), basically resetting the fight. I also recommend Cleasing Fire to break stun, because there are a number of mobs that will stun you before hitting for very heavy damage.
Best Answer
Assuming Guild Wars 2 is similar to other games, its still early so the exact combat formulas aren't well understood, but usually its a trade off where vitality (HP) dominates early on, but once you have enough HP, toughness/defense/armor becomes more important.
The metric you want to use to maximize survivability is effective hp which takes into account both vitality and toughness. The same goes with power/precision for calculating max DPS.