Set visibility on the categories in the form based on other values on the form. You can do this in the fields/categories within the form fields themself.
For instance if you have 5 fields to capture data but only 3 are needed if you're a business (vs. an individual) you can add a dropdown list with those values (business, individual) and check the box towards the bottom that says has depending fields. Then in the Category for the Business questions in the visibility (towards the bottom) set the macro to DropDownFieldName.Value == 'business'. Then the categories fields will only show when 'business' is selected.
You could also accomplish this by using javascript, although I think the built-in tools will work fine.