The biggest mistake in trying to get anything done is waiting for motivation to do the thing. Motivation is temporary. It will eventually run dry, and if it is your sole driver to accomplish something, so will your path to achieving your goal.

Make the mind tougher by exposing it to adversity. -Epicurus

The strength to achieve something should come with a purpose that does not waver regardless of current situation or any changes to it. Motivation should and can be used as a kickstart to getting things done, but always with the discipline and determination to keep pushing forward when it is no longer a part of the equation.

My personal approach to this is to figure out why I'm even doing whatever it is I'm trying to accomplish. Sometimes the actions we're doing as so far detached from the 'why', that we stop associating the two and caring about the outcome. Finding your 'why' again and keeping it close to your heart is often enough to keep you pushing towards your goal, regardless of how motivated you are.

This is also a good thing to keep in mind as you reflect on your goals. What was the reason your started doing what you're doing? Is it still there or has it changed? These should be plenty to know if you should continue doing what you do, or if you should rethink your approach to certain things.