how can I cut a hole in a glass bottle?

Pick up a glass drill bit in the desired size at Home Depot. Pick up a power drill to go with it if you don't already have one. Keep the hole wet to prevent the glass from shattering. Pick up a small tube of silicone sealer if you are planning to put a tube through the whole.

I've actually done this many times. The best way is like described. Buy a glass drill bit, either a diamond bit, or a carbide tip bit. When you drill the glass it does need to be kept wet. The way I've always done it, is to put it in a shallow bucket of water, with the water level just covering the hole. The drill bit can get wet, but just don't get the drill itself wet. Here's a couple things to keep in mind. If you put too much pressure on the drill, when you eventually get through the bottle, you may smash into the other side, breaking the glass. Wear heavy gloves in case the bottle does break. Have some extra bottles in case you break one. When drilling, if you keep breaking the bottles, you can drill a pilot hole and then use the bigger bit. If you plan on running anything through the hole, you will probably need a metal file to smooth the edges. Good luck! If there are any problems, let me know.

go. really. slow.

I purchased a 1” bit from Diamond K, which works ok , but it is a little too big of a hole. Then I got a 5/16 from Lowe’s. I never did get it to go thru the wine bottle, and broke about 8 bottles trying. They were both diamond drill bits @ $23 ea. I wanted to give these as gifts for Christmas. I am still not happy with the results. Any Suggestions???
BJ