Play the game like you would a single player rpg, It is an MMO but every person/toon is responsible for their own ass. Thats how I see it, like a co-op+ rpg. Like playing Skyrim!, you dont have a tank and heals, you bob and weave, healing what you can when you can. Really simple strategy. You don't just stand there and get blasted in the face repeatedly, expecting to live through it, you stick and move.
Go play Demon's Soul/Dark Souls and then come back to GW2, you'll find it to be a breeze, that is if you don't rage quit either of the former in the first 15 minutes.