You could create a “New Record Button” on the form using this code:
Private Sub Command20_Click()
On Error GoTo Err_Command20_Click
DoCmd.GoToRecord , , acNewRec
Or you could put this code at the end of the code of the button you already have, to automatically clear the form after adding the record to the database.
This site has an interesting discussion dealing with the exact same issue that you have. You might find it helpful.