Preparing the juice, fruit wine on the table, or you have a bunch of fresh fruit, make sure it will be lots of flies appear from nowhere (wine or fruit flies). This video shows one of solutions how to get rid of them.
I like taking a used water bottle, cutting the neck off about 2 inches down putting a slice of banana in the bottom, poke a hole in the lid big enough so they can get in, put the lid back on the other part of the bottle and tape it on there. Leave your bottle trap by other fruits or put the fresh fruits in the fridge for 2-3 days or in a bag. Leave catcher(s) out for a few days and throw out when needed.
I follow MaryB's path, with small dishes of cider vinegar with a bit of dish soap. Works pretty well. Lee Valley sells a trap that works even better, but that gets pricey pretty quickly.
Using the little jar method last summer I picked up one small trick that sped the process way up. It's a small thing when using a small jar/ glass method --- use a bit of plastic wrap across the top held tight with a rubber band and poke small holes in the plastic wrap. The flies have an easy time getting in, but getting out is a much more difficult. Once trapped, they get down into the liquid a little quicker.