Read their reading book everyday to ensure they are getting reading mileage.
Early reading books are designed to be read first in a guided reading lesson (with the teacher), then immediately afterwards with a buddy (paired up by the teacher) and then at home with you.
Work on the 36 high frequency words that I have sent home.
The sooner they get the first 18-20 words the better so it is important to work on these daily. Start with 3-5 words and add a new one as they learn them.
Work on their alphabet … all the letter names and all the associated letter sounds.
Alphabet knowledge is an important tool for decoding words.