So many dogs are happy-go-lucky and confident and up for adventures. Lately, I'm meeting quite a few fearful pups--and we can do a lot to make them feel better.
Some humans are tempted to rush the process, but fear can dissipate only when the dog is ready. If, for example, your dog has moderate separation anxiety--perhaps chewing things especially at exit routes and maybe peeing when you're not home--you've got to make the time to help him through desensitization and counterconditioning. (Ask me for more info!) You may have to use doggy day care or have friends stay at your place or take your dog to your job as you work on getting him used to being on his own. Any time he spends by himself in the meantime can just fuel his anxiety. Patience is crucial--and kind.
Even some puppies are fearful right from the beginning, sometimes thanks to genetics or bad experiences even before they are eight weeks old. They need to adjust to scary environments or strangers or other dogs at their own speed. Why rush it?
If you were afraid of snakes, I wouldn't bring you into a room crawling with them. We'd start by maybe letting you see one asleep in a secure tank. If you ate chocolate chip cookies while admiring the snake from across the room, you would probably sign up to visit Sammy the Snake again very soon.
Short sessions at the pace of the dog. Lots of great rewards the dog enjoys--food or otherwise--and patience will pay off. Taking your time with fear doesn't mean it takes a long time to deal with fear--often just the opposite--but it takes however long it takes.
And even after things seem pretty good, reinforcing the positive is still necessary sometimes so the dog doesn't backslide. Your dog's separation anxiety seems to have gone away--so once in a while, use some of the same tools you used to solve the issue just so he stays secure. Go out and come right back. Pick up your keys for no reason so the cue isn't so important. Don't make a fuss when you come home. Give a treat when you leave. Keep the TV on for company. Let's keep fear under control if we can!