Find your vein Tourniquet on. If at first you don't succeed If you are still calm try again. Let the child know exactly what you are going to do before each step. Let them feel your confidence. Don't stuff them around and don't let yourself be stuffed around.
Parents are optional.
Sometimes they are helpful sometimes they are not and there are no simple rules. If the child is less than 1 year old you are all probably better off without them.