Do not hesitate to ask students to do their papers over if they submit papers that are written carelessly. If a paper is written beautifully but the name and date on the paper are scribbled, refuse the paper. If students are to form lifelong habits of good writing, everything that they write must be done well. Be consistent and strict if you want excellent results from every student. Try to improve your own handwriting.
Students are very quick to criticize.
Set a good example.