More positive me is here now, sorry about that.
Portage can be very helpful - they tend to do at home sessions unless in preschool, then they switch the support to the preschool setting.
I taught DD2 eye contact by daily lollipop lady crossings ("We look at the lollipop lady, we smile, then we can look away again").
DD1 has SN (and ironically, has just been referred for ASD assessment at the age of 15!!) so we were already using Makaton sign language. It can help with reinforcing and giving consistency, even if a child is verbal.
Visual timetables and "Now,Next" can be really useful. You can start them really young. By saying "Now....., Next....." It can bring predictability and reduce frustration. E.g. "Now we get dressed, next we have breakfast".
Reducing your language is key. Children with social communication difficulties will just zone out if there's lots of fluff and nonsense in your communication. It's better to say "Peter, shoes" than "Let's get our shoes on so we can go for a nice walk in the wintry weather!"
If you want to teach a new skill and your child struggle with retaining lots of steps, backward chaining is really effective. E.g. getting dressed. Instead of teaching trousers by foot in, foot in, pull up, try getting them almost dressed then teach "pull up". When they've mastered pulling the trousers up, you add 'foot in'. That way, they always succeed.
Distraction and redirection is useful to avoid saying 'No' constantly.
If you struggle with walking safely outside, either a buggy (Maclaren Major go up to 50kg/8-9 years) or reigns are useful. If reigns are tricky, then Crelling do SN harnesses. DD1 wore one until she was about 7-8.