Change your perspective
If you take a photo and it doesn't look right, not exactly what you were after, then change your perspective. Either move to change the angle, get below your subject or get above your subject. You could even take a photo of the same image from multiple perspectives and then choose the one that best suits your need.
Are you annoyed with the space above?
Don't be. Humans have this thing where they are insistent on filling space with stuff, usually unnecessary stuff. I bet your garage at home has stuff all over the place stored in it, seems a shame to waste that extra space with just.... space... right!
Well in photography negative space is good and you should use it to give your images drama, movement, feeling and a point of difference. Don't be scared to give your images some space!