I show all the fact families with the sum of 7, organized into a table. Seeing the structure and the patterns in this manner helps develop number sense and helps children in the memorization work, also.
Then we drill the facts for a bit. The lesson also includes an exercise where we compare expressions ("alligator mouths") and draw lines connecting facts from the same fact family.
Addition & Subtraction Fact Families — free online practice here at MathMammoth.com
Addition and subtraction facts with 8 — video lesson
Math Mammoth Grade 1 curriculum