My ds has adhd and autism/pda, the toddler years were tough and we didn’t understand what his difficulties actually were at that age. I’m not suggesting your ds has any difficulties beyond being a toddler but some of the techniques for pda work great on all toddlers.
Reduce demands wherever possible
If he’s going in the car/buggy and doesn’t want to put his shoes on it doesn’t matter, just take shoes with you
Make everything as fun as you can as a form of distraction
Sing song voices, funny walks, tell stories, provide sound effects, all kinds of silliness I know this can be exhausting but it really helps. Act like you’re a children’s Tv presenter.
Give choices on everything
You can choose the red hat or the yellow hat! Put them behind your back, let him choose a hand.
Do you want sun cream on your legs first or your arms first?
Be as positive as possible
It’s so great you’re sitting watching Tv quietly (even if he’s only been doing it a matter of seconds)
I love your car noises! They’re amazing
Wow! You look so cool with your hat on!
Praise even the not bad things he’s doing
Rather than “don’t hit” say “be kind, I know you are a lovely kind person”
Avoid “no” wherever possible.
Allow loads of time to do anything or get anywhere. Toddlers hate to be rushed
Explain what’s going to happen several times in advance and offer choices wherever you can. Eg do you want to leave in three minutes or in four minutes?
When he does something wrong frame it as a mistake rather than deliberate. I used to pretend to rewind time with funny noises and then encourage him to try it again.
Eg if he snatches “Ooops! Let’s try that again (make rewinding noises/actions) annnnd action” like you’re both actors in a film
Give them what they want in fantasy, make it ridiculous. When ds wanted to buy toys in a shop I’d say I wish I could buy you every single toy in this shop, I’d buy all of them!! The Lego, the cars, the bikes, the dollies, the teddies! Everything! We’d build a tower with them all the way up to the moon! etc etc getting sillier and sillier all the time moving us out of the situation.
Acknowledge how they feel, then distract. You don’t want to eat this lunch, you want pudding now. It’s hard isn’t it? I get mad too. I want to scream and shout sometimes too. Everyone feels like this sometimes. I wish I could give you exactly what you want all the time. Do you want this toy or that toy to play with now, after lunch would you like to do x or y?
It is bloody exhausting and a lot of the time these things might not work but with perseverance you’ll find variations that can sometimes work for your child. A lot of this is great emotional coaching which will stand them in good stead for a lifetime (you have strong emotions, we all do. They will pass and you’ll be ok). Eventually with perseverance and positivity it will get better.