This will be a short post but it's filled with really important informations.
Im going to tell you something about the movement in PvP and its importance.
Generally it is important to know how much benefits it can have to move all the time in PvP.
When you move, meeles can't hit you as long as they have the same movement speed. You can also dogde projectiles if you move which can be very usefull if facing a ranger or a paragon. But there is something you need to know if you move and the enemy hits you while you move it will allways be a critical hit this can be very harmful if the enemy uses for example a hammer or a scythe. This wont happen if you strafe... you will move slower but you wont get the criticals.
There is another thing you have to pay attention on. There are several skills that punish you if you move. Mostly they deal additional dmg or knock you down which is pretty annoying since you want to escape and not lieing on the ground (: . You have to observe the enemies and instantly stop if they use skills like Water Trident or Bull's Strike (use the cancel button).
I hope I could help you with this info a bit.