Make sure the cloth or fabric you choose is big enough to cover the glass completely when you lay it on top of the glass.
You only need four small pieces of tape, around the edge of the circle.
This is an excellent time to distract the audience with some flourish. Try making an exaggerated gesture over the glass with your other hand as you move it.
Before you remove the cloth, you can increase the entertainment factor of the trick with some magical flourish. Use a wand, or say some made up magic words. It’s up to you, so you can get creative here.
Make sure whatever long-sleeved article of clothing you wear has long enough sleeves to partially cover your hand.
It’d be wise to do some misdirection at this point, so that the audience doesn’t see you purposely letting one of your sleeves cover your hand. Hold the coin in your other hand and wave it around while you talk to the audience, preparing them to see the coin disappear.
You’ll need to practice this trick a few times by yourself to make sure you can reliably flick the coin into your sleeve.
For this trick to work, you’ll need to either have something under the table that will muffle the sound of a coin falling, like soft carpet, or a rug, or you’ll need to be standing so that the hand not doing the trick can discreetly catch the coin.
If your table isn’t over something that will muffle the sound of the coin falling, catch the coin with your other hand. You may need to practice this so that you can do it discreetly. While you’re pulling the coin off the table with each circular motion, do some misdirection with your other hand and voice to keep the audience from looking too closely at the place the coin originally was.
