Do you have any training tips for how to get a cat to use a cat door?
Start with a hungry cat. Hunger may be a good training aid since some cats can be stubborn. Keep in mind that you, the trainer, has to have patience. Some cats get it right away; some cats take more time to learn that the pet door is a portal to fun in the sun!
Limit your training sessions to about 10 minutes. Try not to overdo it. Have the cat on one side of the pet door and you on the other Open the flap so they can see the hole through the door or wall Hold the flap open for them and give them a treat or food, repeat drawing them closer to the pet door opening until the come through - don't forget to give them plenty of praise and verbal encouragement them when they're successfully through. Reverse positions and repeat.
Continue the steps above until their accustomed to going through the opening then gradually and gently lower the flap so the cat can get used to pushing it and the feel of the flap on it's back. Repeat the above steps until they comfortable on their own.
Did I mention the two P's: Patience and Praise? They'll be your best friend