A common trend I see when it comes to fitness and health (and believe me, I've seen this a LOT) is people being way too impatient with their goals. People stop training, stop dieting, and ultimately just give up as a whole. The number one thing that people have to remember is that this is a marathon, not a sprint. If you have a goal set out for yourself, you need to educate yourself and understand that it's not going to be achieved overnight.
Let's take me for example: as you all should know by now, I LOVE to deadlift. However, I've spent four years building up to where I am today. Four years of frustration, four years of patience, four years of just understanding and trusting the process. It was NOT fun all the time and even to this day I still get mad at myself for having a subpar workout. Despite the countless times I've left the gym in a terrible mood, I kept on going.
Set a goal, take the time to plan out the steps needed to achieve that goal, and execute. This doesn't even have to be with just fitness! If you want to get the best possible score you can on an exam, you plan out when and what you're going to study, and when it comes time to take the exam you put all your preparation into it. If you're going for an extremely important interview, try to determine what questions they're going to ask and do some research on the company, and smash the interview. Again, prepare and execute.