I usually talked with my toddlers asking them "why"? Why do you want to stay late? why don't you want to eat carrots?
They were usually thinking about trading and I was patiently waiting.
They do not like carrots (me neither btw), ok, so you get to pick a vegetable.
They want to play longer, ok, you play in your bed. Etc.
Of course this did not work all the time, especially when I was tired and maybe not that patient so more traditional ways of persuasion were used (no, nothing violent, just "do it because I said so")