Dog Health Questions: My dog needs some training and I need help knowing how to do that...?

So my dog is a 3 year old Border Collie/ Dalmatian/ Blue Healer and is very anxious when it comes to new people or animals. He has been to the Pet smart dog training before and learned the basic commands. However he barks very wildly at the doorbell, anyone walking by, dogs, cars, and people. He is extremely friendly but needs to learn how to do these things. How could I train him how to teach him to become calm with the doorbell, anyone walking by, dogs, cars, and people? Thank You very much and I appreciate any answers.

Dog Training - The First Steps in Training a Dog

Recommended Answer:
There are some excellent sites out there that can help you if you wish to go it alone. See:

Adult Dog Training (2 years+) | Dog Star Daily

Older dogs become more wary of the world in general and especially of strange, scary and unfamiliar stimuli. Make sure you give your adult dog plenty of ...
www.dogstardaily.com/training/adult-do… - Cached - Similar

The Ultimate In Dog Training: Schutzhund Dog Training

• Bring him everywhere (not literally) with you and have him sit when people come over to see him. Encourage people to pet him ("would you please pet my dog? He's in training.")... I actually did this last year with one of my dogs, and she is much better about people and other animals now.
  You can get a one-to-one trainer by searching Canine Specialists in your area.
  Bring dog cookies where ever you and your dog go, and when he does something you want him to (not bark at the door bell or other dogs when you say "quiet" or "no") get very very very excited (look like a fool- it's the only thing that really works), ump up and down, scratch him ears, give him a little bit of cookie.
  Work with him. It won't change overnight, but you will notice changes if you devote yourself to changing and helping your boy.