O.K., let's try to find a less-cluttered background. Ordinary foliage will work fine if it is out of focus. The way you do that is to increase the distance that the model is in front of the background.
Then, hold the camera in portrait format for this type of shot. Try to frame your model's head and upper torso. If the frame is larger when you shoot, that's usually o.k., because it will give you some crop room later.
Then, get some additional light on her face. You can use the built-in flash, but that is not ideal, so get an inexpensive reflector for outdoor daytime shooting. Or better yet, get a speedlight and a cord that will allow you to get the flash some distance from the camera.
Hold the camera level, steady, and about the same height as her chin and focus on her eyes.
Apparently you don't need to coach your model, so just let her be herself.