The desire to excel is usually a good thing, but when it spills over into perfectionism it can also cause a lot of trouble, burn you out, and waste a lot of time. The key is finding the balance.
1-Forgive yourself for your shortcomings. Nobody's perfect, and everybody has strengths and weaknesses. That's not to say you should not try to grow. You can always learn something new or try to improve, but there are times when you'll have to go with what you already know and do what you can based on that. Don't waste time worrying about what you can't (yet) do.
2-Ask what's really needed. Is the real purpose to be perfect or produce a perfect result, or is it to get something done? What really matters? Perfectionism can often be the opposite of a timely result, because the uncertainty that comes with it leads to procrastination.
3-Define a goal. Knowing what you want to achieve not only helps you go in the right direction, but also helps you know when you are finished.
4-Get started. Even if you're not sure yet what you're doing, give it a try. You may be better at it than you think, or your task may be easier than you imagined it. Even if your first attempt doesn't get you anywhere, perhaps you'll know what or who to ask to get going. Or, you may just discover what not to do. Most of the time, you'll find that you imagined the barriers as larger than they really are.
5-Set a time limit:
*Some things, such as housekeeping, are never really finished. No matter how well you clean the floor today, it'll get just as muddy tomorrow when somebody forgets to wipe his/her feet. Instead of spending hours scrubbing, set a timer for a reasonable amount of time, and clean for just that long. The place will still get cleaner and you'll work faster and without obsessing over details. Make this sort of upkeep work a regular, brief part of the routine and things will stay at an acceptable, pretty good level.
*On a longer or more detailed project, a deadline, even a self-imposed one, can get you started and keep you moving instead of worrying over details. Break things up into smaller parts or intermediate goals if they're too big.
6-Rehearsal: not just for artists. Create a sheltered environment for learning, one where you have permission to make mistakes. Rehearse. Practice. Experiment. Quiz yourself before the real test. Write a rough draft. During all these processes, tell your inner critic to take some time off, leaving you free to learn and experiment without worrying that you might mess up.
7-Try new things. The accepted method isn't always the best and doesn't always work. Whether you're inventing something or learning a new language, you will have some false starts. In fact, the newer and more unusual an activity you undertake, the more you will have to learn by trial and error. Then, be sure to learn from your mistakes.
8-Recognize that for many activities, especially anything with an element of creativity, there is no one 'right' way, no one 'right' answer. If you're evaluated at all, it is subjectively. You cannot possibly please everybody who reads your writing or gazes at your painting, for instance. While keeping an audience in mind can help give your work direction, you should also allow for a large element of personal expression and style.
9-Recognize the beauty and benefits in imperfection. Dissonant harmonies in music can create tension and drama. Leaves left on the ground insulate plants' roots and decompose to nourish the soil.
10-Reflect on your failures. Failure is relative. Perhaps you thought your cookies were a bit overdone, but everybody else gobbled them up. As the doer, you probably know more about what went in than anybody. Whoever benefited from your work cares more about the result and may never even notice the process. In addition, consider what you learned from your failures, and how that will help you do a better job next time.
11-Reflect on your successes. Think back to something you have done or made that was successful. It may not have been perfect, but it still achieved a goal or objective. Probably you experienced some uncertainty along the way to creating that success. Your reservations and concerns may keep you out of trouble, but don't let them drag you into inaction. Rather than do a few things perfectly, accomplish many things successfully.