Novice
Form elements follow few or no best practices.
Competent
Form elements follow best practices: clear labels, appropriate hints to the user, appropriate controls for different user inputs.
Proficient
Forms follow conventions and best practices, and have also been refined to match the users' mental models, as well as reduced where possible to cut down on fatigue.
Expert
Multiple approaches to the forms in the product have been tried and tested, with clear evidence for how the proposed forms are efficient, and match the users' needs, expectations, and mental models.