I'm considering repainting my rather dark kitchen unit doors to brighten up
my kitchen. They're a dark wood, quite heavily varnished and with a strong
grain.

I'm planning on taking each door off its hinges, sanding and painting them,
then remounting them once they've fully dried. Are there any particular
precautions I should take when repainting them beyond lightly sanding them?
And in addition (you can tell I'm no expert at this), do I need a particular
type of paint?

Many thanks.