How can I stop my puppy barking at people?

When my border collie puppy was 12weeks I took her to a training class. The man was extremely strict and terrified her. From then she is scared of men especially of those wearing hats as he wore one. Its progessing to others now and she gets scared of any people that approach her. She has nevershown aggression though. How can I stop this as she's so scared and it's also embarrassing.

take her to a nicer trainer because she might get over it

Take her to a nicer trainer and tell her no!! Also give her treats when she is quiet border collies are VERY smart the smartest breed in fact I know that if you introduce her to nice people with hats (that slip her treats) she will get over it and see that there are good people too

You can try a trainer, but there is a lot you can do yourself. What she is expressing is fear. Border Collies are very intuitive dogs that generally want to bond to and please their human. I have found that, especially in herding breed dogs, females are wired to have a larger personal space...they are also the alphas. Think about it...the girls raise the pups, therefore they have to protect their "den" and the space around it. They also set the rules, correcting the pups with their body language and growls. Males are usually more laid back and have much smaller personal space and are less sensitive to their surroundings.She is young, so there is still time to get this under control. It will take more to desensitize a female to general situations, but it can be done. Training should help raise the self esteem and confidence of your dog as well as build a better bond between you both. Since her first experience was bad you will be doing some unfortunate damage repair. Start small, with situations around the home. Positive rewards will be successful, so reward any behaviors you want. Verbal commands or yelling at them will not work...she doesn't know english. If a correction needs to be made, a low growl toned AAA can be very effective, and since it is similar to the corrections it heard from its mother then it is more readily responded to. But most of all, try to set her up for positive success in situations. If you are not crate training, start. This will give her a "den" of her own to feel safe in....nothing ever bad should happen concerning the crate. The most I do to deter lets say barking if a hush isn't responded to, it a shot of water from a squirt bottle with the command following a second time. They seem to learn commands quickly, and since there is very little body language from you , it is less threatening to them. Try to keep you voice a positive in her eyes. She will work for that. Reward any responses to any command with a treat, whether it is come, sit, down, hush, or even just looking at you when you say it's name (the name game). Another thing you can do to relax her is massage. This can come in handy in any situations you want her to relax versus responding to the situation.As she build self esteem, expand her situations slowly. Start with someone you know and just let them come over for a visit. At first, ignore the dog...have them avoid eye contact with her. Eye contact can be seen as a threat or challenge. The more positive situations you can reward her for, the better. Take her for lots of car rides in her crate when she starts to see that as a safe place she can relax. It seems the more the feel they have survived with out fear, the less they will worry about the next situation. If you see her responding fearfully to a situation, take her out of it. Think of it as fixing the fear outside of the trigger. Border Collies are the best dogs I have ever had. Their intelligence makes them easy to train, but at the same time...lack of training is like the smart kid in school who gets bored and becomes a behavior problem.Spaying and/or neutering should also help reduce any hormonal factors that contribute to their behavior. Also, chew toys, lots, as she will be doing a lot of teething between now and 16-18 weeks. :-)You are obviously trying...good job. I hope this helps.