heepie, I'll try and answer your question because it does seem pointless and destructive to condemn people for smacking if you can't offer alternative ideas. However I will make the following caveats: a)I am not in any way a perfect or even a very good parent, b)it's possible (not sure yet) that my 4yo has some SN so his needs may be a bit different c)I have done this on lots of threads like this before and been gleefully shot down, so if I appear defensive I apologise!
I don't have a nice easy non-challenging child, I have two extremely sparky and difficult and complicated children who drive me round the twist. It's not that I don't get angry enough to smack, it's just that I couldn't even if I wanted to - it's a total no-no for me, maybe due to my background, and also because as I've said I think it's wrong.
I find ds1 (4.9) behaves much better if I ive him lots and lots of notice and warning before transitions - changes between activities are one of his major flashpoints (anything from tidy-up time to going home from the park, or going out). He is calmer and more manageable when he knows exactly what's coming. I try to minimise things like running out into traffic by having him hold on to the pushchair/my hand over roads, and then if he behaves properly he earns the right to walk without holding on. If he buggers me about he has to hold on again.
Similarly if he does play up and home - deliberate naughtiness - I usually try and think of a consequence that actually seems to proceed logically from what's he's doing wrong (not being allowed out in the garden because he's taken his shoes off and put them in the bin, for example). I find that that way I can apply the consequence without having to get angry - I just explain how what he has done has led to what's happening, and what a pain that is for both of us, so he might want to do it differently next time.
I do sit him on the stairs occasionally for the sort of really disordered behaviour that can't be reasoned with, sometimes I'll sit next to him until he's calmed down and then talk to him.
As I said though parenting chez Greensleeves is still very much a work in progress and I do NOT see myself as perfect (or even adequate most of the time). I don't think that conflicts with expressing a conviction that hitting children is wrong - to me, it is wrong.