You need to consider a number of factors, including your posture and how you hold your pen and paper. The type of pen you use makes a difference so experiment until you find one that works well for you.

Today we have a wide variety of fonts available through our word processing programs. One easy way is to choose a sentence that has most of the letters (“The quick brown fox jumped over the lazy dog” is one that is commonly used) and type it using a variety of fonts until you find one that you would like to emulate and practice those letter formations.

Another excellent way for an adult to improve handwriting skills is to take a calligraphy course or to do a self-taught calligraphy course.

I have included a number of sites that should help you. They are mostly designed for teachers or parents or therapists who are teaching kids handwriting skills, but I think you will find many helpful ideas. Best of luck with it.