Naming the form and help texts
The help text of the form such as “Name:” should be placed above the field as it will speed up filling in the form. The eye scans the form vertically so text placed above the field takes less time compared to for example if the text is located on the left side of the form.
The form should be so simple that you do not have to write help texts for the fields. Studies show that help texts a) are not read and b) they confuse when scanning the form and give an impression of a complex entity.
Nowadays one sees forms used with help texts placed inside the form which then slide into a smaller text above the field when filling the field. This can be only recommended when there is limited space such as on mobile devices. A help text within a field can give an impression that the form is already filled.
Every one of us has been fretting with the date or phone number when filling out the forms. Here a good way is to give a hint with the shape of the form and punctuation marks of how many numbers are needed and in which order.
Technically especially on mobile forms when only numbers are required it is good to bring out the numeric keypad. This helps entering the numbers and reduces the amount of spelling errors.
It is useful to give feedback to the user while information is entered into the form. For example it is good to inform if Caps-lock is on when entering a password. The correct sign in turn indicates that the user has entered the required information into the field.
Predictive text input eases usage
Particularly in mobile devices filling in address details is frustrating. Here predictive filling of address fields is useful because with just one selection all necessary information related to the address are filled in. The field can in the case of e-mail address for example suggest the most common e-mail endings such as gmail.com after the @ sign.
When searching for the nearest office it is really useful that there is no need to fill in the entire address but just the postal code will give you the desired search results.
Entering credit card information
Entering credit card number into the encrypted fields is difficult. One good way for identifying the credit card information is to have a possibility to take a picture of the credit card of which the numbers are then automatically recognized.