I've seen one "trainer" advocate getting on and off different sides, as part of the backing process. The constant rebalancing encourages them early on to stand square and place themselves in the best position possible.
I'm currently training my boy for showing in hand this year. Don't think he has stood square in 12 years so I had a hell of a job lol to teach him! His breeder is showing me the way of showing arabs, so taught me to do it like this...
Walk him forward briskly and come to a halt then back him up one step. Continue this until he stands square. Then I would wave my long whip around his legs (not hitting him obviously!) and clearly say LEGS (as this is what I will be doing in the show ring) then lots of praise while he stands square for say ten seconds.
Overtime this process got shorter and shorter and he will stand square for longer. The aim is for him to be as good as his sire. Doesn't matter what he is doing or what has his attention, say LEGS and he automatically stands square lol
I now expect him to stand square whenever he is halted in hand, he is getting really good!
Easiest to start the training on the ground, every time (and I mean that litterally) you stop when leading just push him back a touch or physically touch a leg until he's stood square - before you open the gate to turn him out, when you bring him in to the stable - maybe say 'stand' or something similar so he starts to learn what you're doing. Very calm quiet corrections but religiously every time
Lunging can take a long long time !!!
Mine was taught properly (not by me but a pro) and every time he stops he takes another small step and stand square without any aids from me, whether I'm on the ground or riding, - it's just a habbit developed over years.
The young lady who helps with my ponies is going to show one of them in hand this year so I paid for her to have a lesson in the techniques and ringcraft
There is quite a bit to it, I was very surprised!
The lady said (as per what others have said above) that you need a word to tell them what you want to do (in our case its 'stand up') and to stand them every time you halt whether thats when turning out or even moving them around in the stable)
Its easier to get them squarer if you move them back not forwards
If you have someone to assist then get them to walk all the way round the pony as what looks square from the side can look awful from front or back if the hooves are too close together or pointing outwards
Thanks everyone, will have to start doing this at all available times!!
If i wanted to take him to some small local shows to practice getting him out and about, will I be seen as silly if I can't teach him this correctly in time?
of course you won't look silly if he can't stand square straight away , there will be lots of youngsters out in inhand classes
i disagree slightly with some of the other posters in that i would always teach a horse to step forward into halt and not step back , they need to learn to step fwd with hind legs under them in halt not step back
down loads the free app "five star dressage" that has a short video on there explaining how to teach a square halt
have fun with him it sounds like he's getting of to a great start