One of my teachers told me that the way to write neater was to draw overlapping circles repeatingly on a piece of paper. She actually took me and a few other students in the morning, told us we wrote like shit, and told us to attempt to make close to overlapping perfect circles on one line, then overlapping circles on two lines, until we filled the entire paper front and back.

Did it work? Hard to say. I was too lazy to continue doing it from that class.

My handwriting usually goes from a wide scale of shit to decent, and it really does depend on how fast you write/if you're drawing the letters. Mechanical pencils have also been easier for me to write with, though I guess it depends on person to person