More tips to not do dumb stuff I have done-
Hang on to the loose end of the tie when your taking it off or on. Some halters have metal nibs on the end and its really easy to have them swing around and smack yourself or your horse in the eye.
Make sure the back fits under chin and behind the cheek well. If it won't go behind the cheek its too small. If it hangs down too far on the nose its too big. They do come in different sizes. Some brands make the horse size huge other way small.
Tuck the loose end of the tie under the cheek part once you have it tied. It keeps it from flopping around and getting in the way.
That's all I can think of at the moment