Some tips for using Google Forms.

Tip No 1: Formats of Data
Although the Forms accepts the data as Text the Spreadsheet interprets it as text, number, currency, %, Date etc. Therefore, you need to format those fields correctly in the spreadsheet. If you are seeking a Date in the form you should ask in the format MM/DD/YYYY or YYYY/MM/DD etc depending upon how it is formatted in the spreadsheet. Suppose a numerical input in the form is  starting with a leading zero the leading zero gets eliminated unless you format the column as text. For formating the columns in the spreadsheet you have to use the 123 button.

Tip No 2: How to delete the Summary Responses
Suppose you want to delete the summary responses and start fresh it is not sufficient to delete the data in the spreadsheet since the data used for showing the responses is stored on Google's servers. You need to proceed as follows:
Open the spreadsheet
Click on Form/Edit_form
Keeping the form open on the popped up window click on Form/Delete_form in the spreadsheet.
Click to edit any field in the form, don't change anything and click on Done button.
Save the form.

Tip No 3: How to get Notifications when a form is filled.
Click on Tools/Notification_rules in the spreadsheet.
Put a check-mark in the box A_user_submits_a_form
Put a check-mark in the E-mail-daily_digest or right_away.
Click on save.

Tip No 4: How to make a Form from an existing spreadsheet
You can make a Form from an existing spreadsheet. The Data Fields should be present in the first row. Click on Form/Create_form and a Form is created using the fields. All Question become  "Text" type by default and you need to edit the questions to make them Multiple choice, Checkboxes etc. as required. After you save the form an additional column Timestamp gets inserted as first column in the spreadsheet.

Tip No 5: How to make another form from an existing form
If you want to make some modifications to an existing form and use it you can do this by clicking on File/Make_a_copy in existing spreadsheet, give a name to the spreadsheet, then click on Form/Edit_Form in the new spreadsheet.