Whatever she's interested in. At the moment, she loves letters, so I'm telling her the sounds they make, and that seems to be sticking with her. She's crap at counting, can't even count to two reliably, but I'm not actively teaching her to count, as she's quite happy singing her rhymes using any old number name ("five three three one one...blast off!" type things).
Just doing whatever is normal to do with a preschooler means they'll learn stuff anyway. Singing, playing, dancing, baking...they don't need proper "teaching". If my daughter wants to learn how to read for herself, I'll help her, but really that's what teachers are for, not parents ;)
All that said, I'm probably too anti formal education anyway, for someone who used to teach. I like the scandi approach. Kids are young for so little time.