If you see a deer and are trying to bring them in closer, I would just use a simple, soft blat. Just be sure not to call if the deer is looking in your general direction when you do. They have an uncanny ability to be able to pinpoint sources of sound with their radars (ear).

If you are blind calling--do not see a deer-- use different tones. There really isn't such a thing as calling too much. You just need to make sure after each sequence of two, three, or four hits that you scan the surroundings real good for movement.
Once you have one coming into you, DO NOT attempt to call anymore. Only call if they turn or double-back then hit a one or two short blat sequence. This is often referred as "calling on the corners".

Do a Google search for Peter Fiduccia + Field and Stream + Deer. He has some short videos that go over some of the general vocalizations of deer that will help you learn how to make each of them. He also goes over when they are used most effectively.

Hope this helps you some.