Some of the things that were listed in our school handouts for parents helping children at home (so talking 5yo's more so, but same ideas KWIM)
* show house numbers when going on a walk (odds & evens when older)
* look at signs & ask them to see if there is a "P" (give the sound not the name)
* play matching games with letters or numbers (then on to words) rather than pictures
*show them words in things around them & get them to look for one that is the same as the one you point to
* READ READ & READ to them, children who are read to do learn to read faster than those who aren't
* count steps, count out food, count cars
* being able to count to 10 or know the alphabet by memory isn't the same as actually understanding how they are used, so just saying lets count to 10 or singing the alphabet song is more about memory of a pattern than understanding of letters & numbers, so it is good to physically talk about there being 8 with one more now 9, rather than 7,8,9 KWIM
*cook, measuring
Children generally learn best when it doesn't feel like they are (even at older ages) & learning isn't linear, often it is a combination of exposure & timing.