If you want to add interest to your crochet pieces, you have a few options. You could crochet pictures or patterns directly into the work. This usually entails either carrying another color along your working row of stitches and switching out as needed, or dropping the color but leaving it attached so that you can come back and pick it up later. The former is the more popular method and it is usually called tapestry crochet. I wrote a blog post about an incredible designer who specializes in tapestry crochet if you are interested in learning more. The pictures and color work are a seamless part of the object and the results are usually patterned on both sides.
Another way to add interest is with embellishments, commonly called appliques. In this case you work up a completely separate object and then stitch or sew it to your work. This is my preferred method of livening up my projects. Some people don't like the small amount of stitching that you can see on the back of the work after attaching an applique, but I don't mind it. I like that appliques add texture and dimension to my finished object. They can lie flat or pop out depending on how you sew them on. A yarn needle and yarn in the same color as the applique work well for this, but you could also use a needle and thread if you wanted the stitching to be less visible.
Here is a hat with a skull applique that I worked up for my Redditgifts Hat and Scarf Exchange rematch recipient.
Here is a hat with a strawberry applique from my Strawberries and Cream Baby Set pattern. This was my first original applique and I'm really pleased with how it turned out.
I am happy to say that I have come up with another applique, my Freebee (Get it, it's free and it's a bee? Ba dum ch). One of the reasons I like appliques so much is that you can take any object idea and fiddle around with yarn until you come up with a shape that you like. For example, I undid the wings on this little bee several times before I was satisfied with their position.
What are your favorite applique patterns? If you haven't found the perfect applique for your project yet, consider inventing your own!