The answer is: as fast as possible
Logging in is no user goal. It's simply a security gate that actually hinders the user in achieving his goal.
A login page should be as clear as possible. Don't display anything that isn't needed.
Provide a clear form that is easy to read and easy to understand.
This article sums up pretty good how you can improve your forms.
30 Seconds for a login is way too much, assuming you only need one identification characteristic (e-mail, username, ID) and password.
What you can do to limit password resets:
Provide the option to make the password visible as cleartext
Give the user a hint if Caps Lock is activated
Give users the option to set password-hints (like Windows and Apple do for example)
If you would provide an image of your current login page it would be easier to find out what reasons might make it hard for users to log in.