Good question, Ondy!
I actually have to do a talk this winter on the same topic and this is a great chance to organize my thoughts for 30 seconds!
I came up with the following main topics, but they would obviously vary by genus or section:
Water amount, frequency and quality, winter rests as appropriate
Temperature and temp changes seasonally
Potting medium/Pot material
* - Whatever certain thing you do that you think makes your plants happy. I've never read poetry to mine, but they seem to thrive when I bagpipe around them.