To start off with I would suggest doing some attention exercises, in the house or on leash. Say his name, if he looks at you, treat! When you say his name you want him to look at you for something awesome! You can go to varying when you give treats etc.
Have you done recall work inside? If yes, keep it up, do more, use some good treats. Do the name thing too (a clicker can be a help with this). Progress to outside but use a long line and some great treats (you might have to reel him in occasionally). Start at a couple of feet away, at first give a treat EVERY time, then go to variable, then when you increase the distance give a treat every time (I'm sure you get the idea). This is without additional distractions, when you get pretty good throughout your entire back yard add some distractions. friends, family around etc. If things are going really well, and you are able, add another dog to the mix (this will probably take a while).
It takes a LONG time to get a good solid recall, it shouldn't take too long for just in your back yard with not too much distraction (assuming you don't have neighbour kids screaming on the other side of the fence or whatever

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Anyway, that's kind of what we did, although I admit distractions got upped sooner than they should have, we weren't as consistent as we should have been, we made mistakes but despite that we've got a reasonable recall. Caeda got out of the house one day and I called for her while she was exploring the wide world and she was back within a minute....so it does work, though wouldn't guarantee I could call her off of a deer just yet.