Taking all of the opinions above in consideration, plus my own experience in using and designing web forms, I’ve come up with these best practices.
Position the Primary action to the left
Having the buttons aligned with the left side of the form makes a clear path for the eye to follow. By putting the Primary action to the left of the Secondary action it’s also positioned first in the tab order.
Label the actions in a natural language
By describing what the action actually does, the user feels more comfortable using it since he know what to expect.
Make the Primary action stand out
This makes it easier for the user to choose the option that’s most likely without making it harder to find the other option.
(Almost) Never use a Reset button
Reset buttons often hurts user more than it helps them. The only time it’s called for is in a form that the same user uses over and over again with different input. If you use a Reset, also try to provide an undo function.