Our approach has evolved over time... When DD was still very young (under 2), we did the "gentle touches, please" approach that others have mentioned. Around 24 months (maybe a little later) we began introducing responses like: "in our family we use gentle touches," and "we don't hit in our family." This change, to responding in a way that is inclusive of our entire family and its values, has been important for ME during those times when I'm at my wit's end from being tantrumed at all day!
With this toddler discipline stuff, I have to constantly to remind myself that it is my job to keep my family safe and healthy, even if they don't always like my choices.