Number one, you have to be able to print your own work to get really good-looking results. It's worth the extra expense. In terms of setting up your shots,and some other things to try, I will offer the following list of suggestions. Though by no means a complete list, it should help you to begin to get some satisfying results. Take your pictures outdoors in open shade.
Direct sunlight creates harsh shadows.
Simple and direct shots are best for beginners. Avoid clutter, which will take away attention from your subject. Fill up the viewfinder with your subject. To get a more natural expression from the subject, tell them it is not necessary to flex their hardest. A moderate flex will often give more flattering expressions.