So can your dog walk nicely on a lead? or does he pull full steam ahead? Obviously he's in a hurry to get to the dog park and us humans walk very slow on them silly 2 legs of ours! Sometimes a dog walk nicely because they like to be by our side, and other times they will pull ahead, because they have learnt this works, whenever you're letting your dog pull, you are actually letting him practice this behaviour and getting him to stop will be much harder.
So how do you get your dog to want to be by your side? Firstly having a strong bond with your dog is a great foundation for any training. Instead of rewarding them for pulling by getting ahead, think about what you would like your dog to do instead? So you would like a loose lead, that looks like it's smiling, well whenever that lead is smiling, drop treats on the floor by your feet! WOW being by the humans feet means lots of good treats, then when I pull forward I don't get anywhere, yes that's right, stand still!
If you have a multi-dog household, it is really important you spend time with one dog at a time, teaching them to walk nicely on a lead, this will make things easier for you and them. Eventually you can aim to walk them together.