I think that thing where you get the dog to walk by your side is called "heeling" eg following your heels.
I think healing is what you do when you're sick and getting better.
Gotta love the English language.
Definitely take him for a 30 minute walk before class (if he's over six months), and arrive 30 minutes early for greeting time and a little bit of practice in that environment - if there are no dogs around to greet when you first arrive. Practice in as many different places as you can find.
I found with Frosty, it would be all good in the back yard, then no good on the footpaths, then eventually I got her all good on the local ovals... and no good on the footpaths. She's very good at dog school - probably because I insist on her working in a way that I don't in the back yard or at the ovals. Still no good on the footpaths. Got a harness, now she will heel if I ask on the footpaths, but mostly I let her walk ahead a bit and sniff, unless we're at a road crossing, then sit and heel.
Bizarrely - she always goes on my right on the footpaths - no matter which side the road is, and she goes on my left for everywhere else. Agility requires a dog that will work from both sides so I don't fuss about it too much.
Each new environment required me to start over from the beginning or at least step back the level of expectation eg - 15 second stay, not a 30 second stay etc.