My plans for formal early years teaching all came to nothing.
Getting prepared early, when Helen was two I read Diane McGuinness' Early Reading Instruction: What Science Really Tells Us about How to Teach Reading. This convinced me that a properly designed phoneme-centered phonics system was the sensible way to teach reading (despite having myself learned to read without contact with any such thing). And I then bought an actual workbook, the Jolly Phonics Handbook for Teaching Reading, Writing and Spelling, to get an idea how that worked in practice.
I photocopied the first few sheets from the workbook, teaching the standard s-a-t-i-p-n sounds, and every so often offered to teach Helen how to read. But she never showed any real interest, so all of this went nowhere and she ended up learning to read once she started school. (That happened pretty quickly, and it may have helped that I'd been explaining coherent grapheme-phoneme mappings to her whenever she did show an interest in writing, but I think the school motivation and my direct modelling were bigger factors.) And my research was useful background when we were looking at schools, though it turned out that every primary school we looked at had what seemed like a sensible approach to teaching literacy.
On the mathematics front, I bought a copy of Zvonkin's Math from Three to Seven and was inspired by that to think about fun mathematics to do with small children. I even prepared activity sessions (on frieze symmetries and number partitions) for afternoons when I was looking after Helen and one of her friends, but they've always been having too much fun just playing (her friend is noticeably keener when I offer to do something with them than she is). I'm wondering if this might work better in a school context, but don't really want to "beta test" activities on a full class.
Completely informal activities, like playing games with the house numbers whenever we walk anywhere, have worked better. It's harder now, since she walks at near-adult speeds, but I point out prime pairs and attempt to teach her factorisation; I have no idea if this will work.