Create a preschool "notebook."
This is not something they write or draw in . . . instead the pages are already made, and printed out, and then you and your preschooler will talk about the pictures/sing a song/ do counting, etc. for just a few minutes each day.
When I was homeschooling with a large family, it was part of our routine to always have a young child do his/her notebook first, right after breakfast, while the older ones were getting started on some kind of independent work.
We thoroughly enjoyed going through these simple pages (with an alphabet, letter sound activities, counting, days of the week, etc.) repeatedly . . . the same few pages would be in the notebook for at least several days, and often a week or longer, before switching in some different ones.
Here are some pictures of some of the pages in the "Preschool Beginning Notebook Set I," made by Gentle Shepherd (similar to the type of pages we used-- but these are made to be computer print-outs, and our original ones were hand-made with markers on paper).
You can find this set of 15 printable pages at: http://www.gentleshepcurr.com/preschool-beginning-notebook-set-i.html