If your search "eye exercises" on the internet, you can find many websites which can teach your how to perform an eye exercise. Many of them are very simple. But I'd like to remind you that you should perform them gently because our eyes are very delicate, they may get irritated if you rub your eyes with dirty hands.
Eye exercise can't improve your vision. You can wear a pair of prescription glasses to correct your vision problems. If you have bad eyesight, you can consult your doctors for appropriate treatments. It is said that lasik eye surgery can help correct many vision problems. So you can check to see whether you are a good candidate for lasik eye surgery or not. Many people have vision problems nowadays. I think this is result from the development of high technology. With the development of society and technology, we get more new inventions such as TV, iphone and computers. They provide us more fun but also impair our vision at the same time.
There are many kinds of eye exercises. Some people claim that these method can help correct vision problems. But some people said that they can't do that. I think they are good for eye health because they can help relieve eye fatigue but they can't improve our eyesight. There is no scientific proof to show us they can improve our vision. I haven't found a way to increase or strength and clarity of our vision. If you found that, let me know.
You can consult your eye doctors to see whether he or she can give your some reliable suggestions because he or she has met so many patients. They may know a good way to improve your eyesight. Don't trust any eye exercise that will charge you. There is no scientific proof for these eye excercises. So I think they are not trust worthy.