How do I desensitise my dogs to strangers on his territory?

I live in a flat which has a communal garden that we have to go through to exit and Fluffy is much more reactive here than anywhere else. I scan the area before we leave so we don't have to run into anyone on our way out, but sometimes it's unavoidable, especially on our way back home.
He does have some bad experiences with kids chasing and teasing him there when smaller (not nice kids really), so he's scared of them and will bark at them if they are coming towards us. He'll ignore them or anyone else if they are not directly facing us or walking right behind us.

I've tried luring him with treats, but seeing that he's hyped up as he's on his way out or back, it doesn't always work to keep his attention on me.
He's not strangers friendly anyway, but he'll happily ignore them when out, unless they are in the communal area.

Can anyone help please?

I have exactly the same problem with my rescue lab. She used to be a lot worse with strangers anywhere but now it's only around the house & garden & sometimes if people walk too near the car when it's stationary. She only barks at them & wouldn't do anything other than bark but I appreciate that this can still be scary for someone not used to dogs so I make sure she's on a lead going out to the car & when I come home. She'll also bark at the neighbours if she sees or hears them in their garden.

To be honest, I've not really done much about this as I can usually avoid people & prevent the barking & I'm so pleased with the huge improvements she's made everywhere else. I don't need to have her on a lead anywhere else & her recall is fantastic ~ even in mid-chase after a pheasant.

If you want to help your dog cope with strangers in the communal areas around your flat, I think the best way to do it would be to enlist the help of friends/neighbours/relatives. If you can choose a relatively quiet time & set it up so that your dog only meets "nice" people here that are armed with treats & are happy to spend 5 mins or so, maybe a couple of times a day, then perhaps introduce your dog at these times. Don't let them meet you head on or appear suddenly round a corner. Have them standing or sitting where your dog can see them, & approach slowly & quietly, perhaps ask them to hold out a treat & speak quietly to encourage your dog over for the treat. If your dog is into toys, could they have a favourite toy? Make sure that their body language is non-threatening, don't let them reach out to stroke or touch your dog, just offer a treat or toy. If you can spend a few mins chatting to them, & see if your dog can cope with this by making it a pleasant & positive experience.

I had some success with the neighbours by giving them a bag of gravy bones & if they went into the garden & my dogs barked, they would just look over the fence, ask the dogs to sit (which so surprised the dogs that someone knew their names & was talking to them!) that they immediately stopped barking so the neighbours could chuck a gravy bone over the fence. Within a few days the dogs would eagerly put their paws up to the fence & wait for a biscuit every time they heard their back door open. Unfortunately these nice neighbours moved a few weeks ago & I've not had a chance to speak to the new neighbours so I'll probably have to start the whole exercise again ~ but hopefully it should come pretty quickly to the dogs second time round.

Could you sit out there with some friends? get the dog used to the presence of people? Have a BBQ?

Thanks Wilbar, I'll have to find some strangers who live in the flats, but they all keep moving and I don't know many anymore! Fluffy knows all my friends and he loves them so he won't bark at them. And like you I haven't tackled this before.

Thanks Claire, I suppose I could try and do the bbq once the weather is nicer. The problem is that some year and a half ago some people moved in with kids and they let their kids run around every day unsupervised around the garden, the kids are loud, they leave their toys, bikes etc around, and they litter - I do have to speak about this to the management company - as Fluffy keeps finding all sorts of unsavoury things (chicken bones, opened tins, chocolate, dirty nappies) in the garden so I wouldn't let him loose there anymore. Shame as the garden used to be lovely and Fluffy used to play there.
All these things really bring me down so I tend to just walk quickly just to get out there!