Don't whinge / give the latest saga over why you've fallen out with the latest builder. Your neighbour doesn't care about your personal drama making. They are just humouring you.
Don't do DIY on evenings and weekends when the builders have already been in ALL week. Its antisocial.
Try not to let it go on for months longer than it needs to. Make sure you can afford the building work so it doesn't get stalled because you have to stop work whilst you save the money to do more work.
Just because the architects plans say one thing, it doesn't mean that in practice this has to be stuck to the nth degree if an alternative makes more sense.
Do not litter. If you have a skip, make sure it does not have stuff that can be blown into neighbours gardens.
If the building work has been going on for two years, with no sign of end, because you are too busy fannying with unimportant stuff they are likely to start getting pissy.
Don't say that the building work will be complete by x date. It won't be. It will piss your neighbours off even more.
Don't take the piss. If you put scaffoling up which encroaches onto your neighbours property and you don't a) ask permission first b) apologise for it, don't expect them to be happy. Don't act surprised and go "I don't understand what I have done wrong" when they say they don't want to talk to you.
Don't be surprised if your neighbours throw the rubbish from your building work back over your fence after you've put up said scaffold on their property and they've had two years of it.
Don't drive like a dick and park outside your neighbours house like a prick. They've already been putting up with your builders. You are rubbing salt into the wounds.
Don't have a screaming match with your builder in the street over how you can't afford to pay him. It doesn't go down well with your neighbours who've been exceedingly patient.
If your neighbours complain about damage to their property, don't insist that you have to get a certain builder in to fix it, take another month to do so, and then complain about how your ridicilous extra demands for the job are not met. Your neighbours just want it fixed and aren't interested in your petty jobworthiness.
Don't bitch about your builders to your neighbours when you aren't there most of the time and the builders have been more considerate than you.
Don't ask your neighbours for mortgage advice, because your mortgage advisor decided to give you dodgy advice meaning the mortgage on your property is technically fraudalent.
Don't go on about how you are having a breakdown over it all. Your neighbours have been living next to your car crash and know all too well that you've bitten off more than chew and frankly wish you'd just jack it in and sell up.
I could go on...