Push it. And by “it” I mean yourself.
Don't settle for good enough. If I settled for good enough I would be sitting at 235 pounds right now. When I cut out dairy, that was the initial weight that I dropped down to. I took that and used it as a jumping off point. I didn't just want to run a 5K, I wanted a half marathon, I wanted a triathlon. I pushed until I got those things done. Now the goal is to go longer distances, get faster and stronger.
When I work, I work hard. In the gym, I work until I know that I don't have anything left. When I run a race, If I don't feel like slightly queasy after I cross the finish line, I know I haven't done enough. I know that I could've given it more. I need to know that in everything I do, I give it my all.
There's no shortcut. It takes hard work. The fitness models and the people you see in the media, they worked for that. They weren't born like that. I get people all the time saying “Oh, I wish I could eat as much as you eat.” Yes, I eat a lot but you also have to look at what I eat. I had one guy tell me that I should weigh more than him because of the volume of food that I ate. I was sitting there eating bananas while he was scarfing down sausage biscuit after sausage biscuit. He didn't take into account that I'm eating fruit. He had no idea that I was going for a 5 mile run just a couple hours later. He didn't know the effort that I put into being healthy.
When I was heavy, I'd see people out or on fitness magazines and think to myself “I'd like to look like that.” And, yeah, I'd hit the gym every now and then. I'd get on some sort of exercise kick and drop 20 pounds. I never pushed myself though. I never changed my eating habits. On the contrary, I probably ate more and worse than when not on an exercise plan. In reality, the results come from what you eat. So, I always said I wanted to look a certain way but I never really did anything about it.
By pushing what you think your limits are you'll find that you're capable of much more. I read in a book somewhere that when your mind tells you you're done, you're really only 40% done. So when you feel like you're done, keep going, you'll really surprise yourself.