Well with leveling you can always take varying routes, but 10 in arcane is always a safe bet. Bar none our most important trait in any of the trees is elemental attunement at 10 in arcane so you can pick up the boons on attunement switch, as well as increase your boon duration and reduce the attunement switch cooldown through the passive bonus from points in arcane.
From there, 10 in water is another safe bet, giving you some health regen while in water and especially the 10 point trait “cleansing wave” in water letting you remove a condition when you switch to water which is useful even in lowbie PVE.
From level 31-40 you can do whatever you want really. At level 40 you unlock the ability to go 20 deep into a traitline, allowing you to pick up another essential trait “Healing ripple” at 15 in water, which heals you switching to water. Combined with the 5 point water trait, 10 point water trait and 10 point arcane trait, you’ll now gain regen, “soothing mist” (which is like regen but weaker, but stacks with regen), remove a condition, and directly heal yourself as well when you switch to water. When you have all that you’ll be much more comfortable staying in the fight with dagger/dagger. Protection boon you’ll get when you switch to earth due to elemental attunement will help keep you alive as well.
If you want to head towards the cookie cutter “bunker” elementalist build, which isn’t a bad idea at all, you can go on to 20 in water and pick up “soothing disruption” which gives you both regen and vigor any time you use a cantrip. Put armor of earth, lightning flash, and mist form on your utility bar at that point. Great utilities in their own right, and all 3 are cantrips. You’ll hear new elementalists talk about how squishy their elementalists are on this forum in PVE sometimes. You will not be one of those people if you trait that way.
That’ll take care of the first half of your leveling and give you core traits that almost every elementalist is using (for good reason). Unless you have something specific in mind, going deep into water and arcane is probably your best bet right now (I use 10 air, 30 water, 30 arcane at lev 80).
Nice thing is it functions properly in both PVE and PVP so you don’t need to do anything weird with your traits if you like to mess around in WvWvW.
