Leashes, Collars, Harnesses, OH MY!
So many options! I know.
When we started with our first puppy, I absolutely loved this
a Martingale collar, to help with teaching proper walking techniques.
https://www.petvalu.com/ca/product/martingale-collar-blue-paw-print/SCM07815CA
But since we have grown with dogs and adapted to multiple doggies, I really like the simplicity of a slip lead, easy on, easy off, no muss, no fuss.
https://www.petvalu.com/ca/product/rope-leash-blue/SCM06486CA
A great puppy sized collar for aussies is the 5/8s width and 13" length collar, which is a fairly standard size in collars.
I don't use or promote harnesses or halti's, harnesses especially because they impact fluid movement, musculature, and joint articulation(also they pinch, and rub, they can cause skin irritation, hot spots, and hair loss). Train first.
I send each puppy home with a clicker! ^^^^^
Puppy Culture promotes ATTENTION as the "mother of all behaviours", and I can't agree more. Clicker and treat EVERY positive eye contact, and your pup will know you value their attention too. Remember to reduce the stimulus (**LESS DISTRACTIONS** ie. bikes, cars, kids, lawn mowers, construction - are all HIGH LEVEL distractions... work up to these things, and don't get discouraged as you work through these difficult exposures. Take a step back, practice in peace and calm, and then try again).
https://my.madcapuniversity.com/sign-in/
Side note - I caution leaving collars on dogs for extended periods of time, for one they can be a choking hazard, they should be removed during play sessions, as I have seen dogs jaws or teeth get caught in them, and it usually causes both dogs to panic, it doesn't typically end well. Collars can also get caught in things around the house, I would hazard against leaving them on. That being said, if your dog bolts out the door, or is an escape risk, you will need to weigh the risk/benefit of keeping one on your pup! The best interest of your dog is the #1 priority.