Model consistent excellence (as much as possible) for the students. If you want them to be prompt, you need to be prompt. If their assignments should be turned in on time, you should give assessments and grades in a timely manner. Report cards should be handed out on schedule, not a few days after the deadline. If you want neat handwriting, write neatly yourself on the board and as you provide written feedback on their work.
Providing an example of excellence will not magically produce excellence in students but it gives one a good foundation to build upon and require excellence from students.
Also, recognize that excellence in all things is not attained quickly.