A goal is a target to achieve, usually in the long term. It requires an understanding of what you desire to get and the things you must do along the way to get it. For most internet users, the object is usually to make money at home to free yourself of having to report to a boss because making money at home means you are your own boss, and you set the terms of work and play. Internet business, however, is just like any other business. Which means you must have a burning desire to succeed...
As you know GA is an application to track the website traffic with various data like page visit, unique visit, organic traffic, traffic from keywords.... The Goal setting or Goal creation in GA is completely depends on your requirement. For example traffic on particular page, Average time on site, no of pages visit etc.. Hope it will be fine.. For further detail just start with Google analytic Goal creation and in case of any further query let us know.
A goal is simply something you find useful - that could be a sale or a sign up to your newsletter. Only you know what actions you deem valuable on your site. The point of having a goal tracked on GA is to see how well your site is set up to achieve that goal. It could for example tell you how many people move from your home page to your contact page. If not enough people are doing so, you can make changes to your site to try and encourage more of the desired behaviour e.g. add a large 'call to action'