Ok so I'm a owner for 6 years (thats his age also) with a dog who doesn't get along with other dogs. He is mixed between a collie, sheepdog and labador. Because of his stupid behaviour, we don't go anywhere else besides the same old place which I wish we would to get out more outside our area. What should I do to make him less dominant to other dogs?

Has he been neutered?

Has he been neutered?
Sorry forgot to say, he has.

There is nothing you can do to make him like other dogs.. he is who he is.

You don't have to go to dog parks to enjoy your dog. Go to state parks, forests and blm land. I own a pit and she is all pit.. doesn't like other dogs... so we don't do activities that involve other dogs.

Behavior training and obedience will help a lot, but it won't turn him into a dog friendly dog... but it will train both of you how to control his aggression and teach him to behave when a another dog is around.

My dog used to not like other dogs as well. He used to get into fights with other dogs to show dominance or out of fear of other dogs (at least that's what a trainer told me). I slowly introduced him to other dogs by first letting him be around a really really submissive dog to show him that it's OK to be around other dogs (my dog didn't try to fight this dog because the submissive dog went into a submissive pose every time it met another dog and my dog was OK with that). I slowly introduced him to more dogs and he is a lot better now.
Also, I have seen dogs who are more aggressive on leash, not sure if that is the reason for your dog's behavior or not though.