Different handwriting programs recommend different teaching orders. It’s a good idea to teach and practice the letters in groups based on letter formation commonalities.
This product provides education illustrating why this method, which works with almost any style of teaching letter formation, helps kids build on what they’ve learned. It also helps to prevent those common issues like reversing letters (e.g., b and d).
There are also handy pages for uppercase and lowercase letter groupings to help children learn to form letters based on their shape.