Frame in a Frame
Sometimes you can make use of your environment to really emphasise the subject of your picture and this leads to stronger composition.
If you can find a situation where you can frame a subject within a naturally occurring frame in the image it can work very well and direct the viewer to whatever you want them to focus on.
In this video I'm using beach huts whilst on a shoot with my landscape photographer friend Tom Mackie just to demonstrate the technique. But frame in a frame technique isn't just for portraits. You've probably seen images of landscapes naturally framed through a cave entrance or overhanging trees, a view through a window which includes the window frame itself.
Try using different focal lengths when you compose Frame in a Frame images. There will be times when you need to exclude areas and changing the field of view to keep the frame tight will help.