If you're setting big goals, it doesn't all happen over night. It make take years to hit your goals so it's easy to get discouraged. The best thing I have have to do is to break them down into days. Learn to dominate the days and reward yourself when you do. Those daily hits of dopamine are going to help keep you motivated! The wins can be as simple as making your bed or refusing to eat a donut. Create a habit of winning.