Do you have optional fields on your form? If so, consider hiding them. Optional fields are less important than required ones, so they shouldn't distract users. However, they often steal the user's focused attention and slow down their time to complete a form.
Focused attention is the ability to concentrate on a target stimulus for a period of time. Humans have greater focused attention when fewer distractions are affecting them. In other words, removing visual distractions increases their ability to focus.