Do you trade in money or prizes, toys or lollies, or are you more of a goodwill kind of guy? Whatever the case is you will need a currency as the kids get older, something that you can reward them with or furthermore bribe them with.
One thing that I’ve learnt over the years is that there’s not quite a currency like attention, and by this, I don’t mean avoid and ignore your kids until you need then to do something. This may work in the short-term, but will ultimately result in you creating sociopaths.
What I mean is, spend some time with them, actually read books and be proactive in their interests, this is very much a currency, not all gold glitters.
By being there you can be attentive to their needs and adjust behaviours as they arrive as well as instil great morals and ethics that they’ll carry for the rest of their lives. This is not a currency that you bandy around when you see fit, or as good behaviour arises, this is a currency that should be universally available to your kids.
The simple truth is, be there for your kids.