RuhRoh is 4 months old and hit a normal fear period the week before last. When she and I went to get in the car she spotted the garbage can on the curb and started backing up and giving a low 'woof'. The same garbage can that has been there every week that she paid no attention to previously. So we walked over to it, at her pace, rewarding every step of the way until she was no longer concerned. You can see at first her tail is swishing rather than wagging. She moves forward then backs up. I've attached the ring video but it's not the best quality.
Saturday we tried to go to the home improvement store but she let us know she did not want to do that. Instead we hung out in the parking lot, watching people and carts go by. She got lots of treats when she engaged. Then we left. We didn't push it any further, just went home with lots of rewards. This way she was left with the positive rather than a scary impression if we'd tried to push her.
Thursday we made another trip to the home improvement store and she rocked it. I had no goal in mind, just following her lead. She was excited, showing none of the fearful behaviors from Saturday. She wasn't hiding behind us, she was wiggling with excitement (her back end wiggles so hard she smacks herself in the face with her tail), she gave little barks (well, for a Great Dane they are little barks) to get people to pay attention to her and as soon as they looked she'd wiggle even harder.
This is why I tell puppy people not to make too big of a deal when something that was normal is suddenly causing fear. Don't make a big deal of it, reward the little interactions (if they look, if they get closer, if they don't hide) so that a positive impression is what your puppy is left with. If it's a normal fear period your dog will grow out of it fairly quickly. If it's more than that talk to a trainer who specializes in treating fearful dogs using reward based methods sooner rather than later.