Advice on creating effective forms
For information on how to create forms from the ground-up, see: How to Create online forms: The basics
One of the most important pieces of advice for creating forms is to ask only for the information you need. For example, forms may ask respondents for a physical address when there is no plan to send snail mail or visit that person. No one enjoys filling out forms, and the longer the form, the greater the chances that users will decide against filling out a form. To maximize a form's usage, they should be as lean as possible.
The Select field is used to create a drop-down of multiple options, of which you can select one. Since this obscures the options until clicked, it's a good way to keep your form compact.
The Radio Buttons are used to create a list of options, of which you can select only one. All the options will appear, so it's best to use this where there are only a few options to keep forms from getting too long.
Checkboxes are used to create a list of options, of which you may select multiple. Only use this if you are sure you want people to be able to choose possibly all options you have listed.
The Replicator group is used for creating multiple sections of fields for the same thing. So, e.g. if you were signing up children for soccer, your replicator group could ask how many children you are signing up and then for each child, it would ask age, skill level and t-shirt size. More on that here.
In the Prebuilt tab, you'll see two fields which validate for proper email addresses. The advantage of the Auto Reply Email field is that it will 1) send an email once the form is submitted. But more importantly, 2) it will send that email address a copy of what they submitted. This is great for effectively providing people a confirmation.
Also in the Prebuilt tab, there is a City/State/Zip field. By default, the chosen state is Alaska. Since it's more than likely that few people filling out your form are from Alaska, you can go to the settings of this field to set a default state.
If you'd like to receive a notification via email every time someone submits a message, you can setup the form's Alert Email from the form's settings. Unless you plan to login to the website frequently to check for new responses, it is advisable to add at least one email here.