Make a goal as to how many pieces you want to submit to publishers. For me, my goal is to submit one work of mine to a publisher every week. The more you submit, the less you feel down about rejections. If you submit only one piece per six months, one rejection will sting much more. If many submissions are circulating at the same time, than you can hold on to more hope.
Not only is submitting lots of writing important for your morale as a writer, it is a good feedback system. You get to see what editors and the public enjoy. Usually, a piece that you enjoy will not be the piece that an editor or the public will enjoy. Sometimes a piece that you despise is liked by others very much.
It may take a while to publish your first piece, but if you keep submitting, it is inevitable that you will be published. After a while, an author builds a momentum. After a few years of submitting your work to publishers on a regular basis, you may have work being published every week or two weeks.