Find some apples that are ready
When you see trees dropping apples, it is a good sign that apples are ready for cider. Many people have an apple tree in their yard and don't do much with the apples. I have found that most people are happy to let others pick them so they dont have to pick them up off the ground and/or mow over them. Offering some of the finished cider to the tree owner is a good way to close the deal.
It may be a good idea to have people collect apples prior to the day of pressing. Unless the apples are stored at around 50 degrees or lower, they may not store well for over a week - especially if there is any insect or other damage to the apples.
Getting a number of different types of apples will make better cider. In general, larger apples tend to give more juice than smaller apples.
On average, a five gallon bucket of apples will give almost a gallon of apple juice.