Wide angle and ultra-wide-angle lenses are among the best tools photographers have for producing dynamic, interesting shots. The trick to using them to their biggest advantage is to get right in close to something while at the same time using the broad view of the wide-angle to take in the surroundings.
To get that effect you’re going to have to move in seriously close to your foreground subject to find the ‘sweet spot’. An inch or two too far away and you lose the dynamic effect. An inch or two too close and you start noticing massive amounts of distortion. When I use my wide angle (10mm on an APS-C camera, which is about the same as a 16mm lens on a full-frame), I will often be only inches away from my subject, so this is obviously not a trick you can use with dangerous or nervous subjects. Well, actually it is possible with dangerous or nervous subjects if you use a remote-controlled cameras, but now I’m getting a bit off the subject.
When I took the photo of the freshwater turtle at the top of this page I was lying on the grass only about 6 inches (about 15cm) away from it. And with the dog photo above, I was less than a foot away from the dog (about 30cm).
Even the smallest movement in the camera or your subject will be enough to affect your composition so be prepared to experiment and also expect to get few bad shots. But the shots that work out will more than make up for it.