Madewell sweater and belt, J.Crew dress, Pour La Victoire sandals
I have not experimented much with mixing patterns and prints but an easy way to incorporate different prints into an outfit is to stay within the same family of colors, balance out larger and smaller patterns, and mix fabrics of different textures and weights. Also some patterns and prints look effortlessly chic when paired together like florals and stripes and polka dots and stripes. There is no exact science when mixing patterns and prints and it really is all about experimenting and going with what you are comfortable with.
A great reason to mix patterns and prints is that it will give you flexibility and more styling options with pieces already in your wardrobe. Recently I picked up this navy and white striped sweater at Madewell and have been wearing it with white jeans. But the sweater is so versatile and a great piece to add to this dress and these printed pants.