Teaching simple letter formation rules can really help kids form letters quickly, correctly, and without tiring as easily. But in my personal and professional experience, it is really hard to fix grip and formation in the classroom alone and the solution may need to include a home component as well.
As a writing staff developer, I hesitate to say the h-word (handwriting). Nothing upsets me more than writing workshop being hijacked for handwriting- or postponed until kids are forming letters to teacher specification. Handwriting and writing are initially two very different tasks. At a certain point, grip and formation can greatly impact fluency for writers, so it is something that should be addressed early on in Kindergarten and First Grade (again, separate from writing workshop).
The first simple fix for helping grip is using a vertical surface, such as an easel or taping papers to a wall. It is hard to use a "hook grip" in this way. A bigger instrument, such as a crayola marker is also helpful in getting fingers in the right position. Chalkboards are also helpful; chalk has a great "pull" when it is used and this helps kids get a good feel for writing.
Formation is key. Letters are made top-down, left-right, and counter-clockwise (except b and p). If these basic strokes are overlearned, this is helpful. Muscle memory is powerful. Practicing these strokes is like learning a new dance step. At first, it seems awkward, but then it is second nature. Practicing these strokes with both large motor and graphomotor activities is a good idea. Also, it is essential to be at arm's length of a child when teaching handwriting to monitor formation. How letters look is not nearly as important as how they are formed. Letters formed properly will be legible and handwriting only needs to be neat enough. When things need to be perfect, they are typed.
Another strategy that is often helpful is to have students overlearn the formation of their first and last names. Just practice forming it over and over again. Starting with the first name and eventually adding the last name. Again, close observation of a child while they are learning this is essential. For most kids, their name will provide ample access to practicing basic strokes. Sometimes just printing the lowercase alphabet once a week, with close observation, can have a powerful impact.
While the name is being learned, continue teaching. Talk about the space letters use: tall, short, letters that hang. Talk about the shapes: curvy, straight, dotted. Connect letters that use similar strokes (such as c: o, e, a, d, g, q, s and r: n, m, h). During handwriting practice time- you are the coach!
Above all, keep it positive. Stop before it's time to stop. Don't push to frustration. Reward working hard - not "good work". Sometimes it may seem like the kids who are struggling the most academically have a harder time with handwriting. So keep practices short and positive and focused on working hard.
There are so many important issues in education. Handwriting seems a little silly to worry about- until you see students further down the line struggling with writing fluency in later grades. I once watched a third-grader print a "t" in three stokes- up from the bottom, to the left from the middle to cross, and to the right from the middle to cross. He was struggling to get his fast, great ideas down with his slow, labored writing. (Also, his first name required 2 lowercase t's.) Hopefully, hooking families in early and having minimal (often only weekly, not daily practice is needed) "coached" practice time can repay your investment ten-fold.
For some kids, practice won't be enough. If steady teaching and home involvement don't seem to be helping, the child may need help with visual-perception skills, orthographic coding, or motor planning and execution. But for most kids, practice makes "good enough".
Perfect is not the goal for handwriting. All handwriting needs to be is fast enough so you can get your good ideas on a page, legibly, and feel good about your work. So, stop and give me 5 minutes of practice this week. Just a few minutes can make a huge difference!
