Most designer in fashion world like Lauren Ralph Polo use appliques to spice up their designs for shirts, dresses, jackets, sweaters and other designer clothes items. And if you want to try appliques on your own, the best way to get creative with it is through trial and error. In other words, the first design you come up with may not look that great. But as you try more and more ideas you will begin to see what looks good, what looks bad, and how to move forward as creatively as possible. Instead of trying out your own ideas, you can look at what others have done for inspiration. This does not mean that you should copy them exactly, but you should definitely take notes.
It is easy to get creative with appliques, it just only takes some practice and time on your part, and of course creativity and imagination.