Why your magicians patter should only tell the spectators things they don't know already.
What makes up a good magicians patter? It should be interesting, entertaining, and move the plot of the magic trick along. There's one thing that magicians love to add into their patter and scripts. We just can't help ourselves.. but we don't need to tell our spectators things they already know.
'I have a deck of cards in my hand.'
'I'll place the lid back on the sharpie pen.'
'I'm going to cut the rope in half, at the middle.'
Your audience already knows this. They can see it! Resist the temptation to fill up your presentation with a running commentary of things that should already be obvious. It's boring and looks like you are giving yourself instructions as you perform. Stating the obvious as a form of magician's patter is lazy. It doesn't move the magic trick forward and does nothing to entertain the spectators.
When you give a commentary about the magic tricks you perform, it should be to highlight unusual objects, create a story or setting, or focus attention on a part of the tricks mechanics that is important for the spectators to remember.
'The three coins in my hand are very, very old…'
'The blade will enter the deck to pierce it's heart..'
'You must hold the playing card tightly as if your life depended on it..'