Here’s the thing; people hate filling out forms. The simpler you can make your forms, and the easier they are to use, the more people will fill them out.
Think about all the forms you currently have (or plan to create) and ask yourself: What is the bare minimum amount of information you need to ask for? The answer should line up with the fields your form has.
Have a bunch of optional fields? Get rid of as many as you can (and you can probably get rid of most of them). Make each optional field fight tooth and nail for its survival. Every form field, optional or not, makes your form that much more daunting and intimidating. If people see a form with ten fields they’re going to move on long before they realize eight of them are optional.
And if some of those optional fields make the cut, make sure they’re visually distinct from the required fields. It should be crystal clear to your visitors which fields they can skip. One of the most frustrating experiences on the web is spending the time to fill out a form and hitting submit only to be faced with an error message and a bunch of fields outlined in red.
Take a few minutes to put yourself in your visitor’s shoes and go fill out all of your existing forms from their perspective. Don’t use autofill or other fancy tools to fill out your forms; many people don’t use them or don’t even know they exist. Be honest with yourself: Do you find your forms frustrating? Do you find yourself getting bored while filling them out? Did the thought of doing this exercise sound like a drag? Imagine how your visitors feel! If you don’t care to fill out your own forms, why should anyone else?
The simpler and easier you can make your forms the better they’ll work, for both you and your visitors.