practice
But also little tips are to run right next to tank but make sure you dont pull.
Once tank has stopped swift a holy which pause the mobs for a bit.
Also learn to recognize certain tank CDs e.g foresight and rampart both do the same thing but you are going to be healing more on one the other.
Get E4AE up as soon as you can
Do not worry about healing the DPS they really shouldnt be pulling, if they do run asap between tank and them and cure 3 yourself as this will mean healing on tank doesnt stop and they should be sorted out.