Have a pre-determined purpose
Going back to the point I made in the introduction, if you have a pre-determined purpose for working hard at something, your motivation will always be there to get things done. Success isn’t a sprint, it’s a marathon and if you aren’t packing the right kind of mental attitude, generated from having a purpose, you are going to fall at the first hurdle. For example the guy who wants to shift some weight, undo 50 years’ worth of bad eating habits and not exercising, he looks in the mirror after a week of dieting and working hard in the gym. He looks at himself and thinks, “well this isn’t working, I still look fat, stuff it, I’m done with this”, he’s thrown in the towel before his body even has a chance to change, he didn’t have a purpose for changing. If the purpose of your change is to look good for the girls on the beach, or to look like all the models on the covers of men’s health or women’s magazine, you’ve got no fight and you’re going to drown. That guy didn’t have a strong enough purpose to keep him moving towards his weight loss goal, if he had thought of a strong enough reason for losing that weight, it would have seen him though the entire journey and carried him though the good and the bad times.