You can try pinpointing the shapes you have most trouble with. If you can’t do straight lines, work on that. If you have trouble with curves, practise those. Any writing is just made up of many different shapes. Keep that in mind if you have trouble, and focus on the steps to making letters instead of how the end result should look.

One good tip I can give that may help you right away is how to hold your pen. I’m not sure if it comes natural to you or not, but holding the pen in your left hand should be different from the right. When you hold it in your right, the end you don’t hold probably points towards your shoulder.

When you grip the pen with your left hand, I find it easiest to have the end you don’t hold pointing away from the right shoulder (in other words, pointing away from you in a diagonal line). See if this helps. You may need to adapt it; the only reference I have is myself.

Still the most important thing is practise. You can learn to write with your feet if you attempt it enough times.