If you do not like that everybody who passes your house can easily look into your yard, think about having a privacy fence installed. Those kinds of fences hide everything from the eyes of unwanted beholders. The best looking privacy fences are made out of wood and to be more exact long boards. This means that they are higher that an average person and the boards are so closely together so that it is impossible to see in between them. One more positive side of that kind of a fence is that it is quite hard to climb over it and therefore it protects your home and when you have a dog the probability that he or she will jump over the fence and go missing is almost zero as the fence is too high for him or her.
Actually you cannot call it a fence, but a good measure against other people looking into your yard is to plant high bushes to block their view. It might look better than a real fence, but it might take more time to have it installed.
So if you want to sunbathe, hang out with your friends or family or just relax in your yard without any distractions and anybody else looking, think about privacy fences.