This tip is actually useful for all kinds of situations that may be stressful for your dog: car rides, vet trips, grooming, administering medication, etc. The important thing in any situation which your dog may find stressful is to soothe them as much as possible and make them comfortable, without allowing them to just misbehave and get out of anything they don’t like! Unfortunately, things which are unpleasant for your dog will have to happen, for his own health and well-being, and it’s important you teach him to put up with it.
It’s also equally important, though, that your dog knows when the stress is over and that things return to normal as quickly as possible. Once the experience is over, tell your dog “it’s done”, and give him a treat. After that, go back to behaving normally. He will soon learn that this signals the end of the stressful experience, and will be content to interact with you normally once more. If you fuss over him, though, it will keep unsettling him – he will wonder what’s going on and what is going to happen to him. This applies before a vet trip as well.