There's an often used compositonal tool called Leading Lines. They're called that because they are lines that lead your eye into the composition, to where the photographer wants you to look.
Take this example here. This pic was taken in the deep, humid jungles of central Africa. The Democratic Republic of Congo to be exact. And these dilapidated bridges were an hourly event on our crossing of this huge country.
The road was in such a bad state that we could often only travel less than 4 kilometres in a day - a day mind you, not an hour!
We came across a lot of small log bridges but only a few really substantial metal ones built by the Belgians. All of them had been looted for their wooden coverings meaning that you could see through to the river far below.
In this particular case I had a couple of choices. I could have chosen to look down through the bars to the river below, or I could do what I did. And that is to take the reader on a journey across the bridge to the rainforest on the other side.
The rails on which I put the viewer's eyes are the metal skeleton poles of the bridge. Because they are prominent in the foreground (a feature of the wide-angle lens) your eye looks straight at them and then follows them up the frame until you get to a part of the bridge where there is more substantial covering.
The other leading lines are those at the top of the bridge railings on either side. They focus your view even more to the very end point of the bridge, right at the base of the treeline. Having a couple of people in the frame shows how precarious the crossing is and by having a lot of empty space in the foreground (ie no bridge coverings) I have not only emphasised the leading lines but also how dangerous the bridge is.
So keep your eyes out for various lines that you can use to lead your viewer's eye through a photo. Just remember that one of the most important things about a leading line is it has to lead to SOMETHING. In other words you need something at the point where the viewer's eye will head to or else they'll feel ripped off having looked all that way to find nothing to look at.
Oh and if you're wondering how we got across the bridge...very slowly. We would creep forward in the truck, placing logs under the wheels. As the truck went over the logs we would take them from the back of the tyres and put them back in front of the tyres again. It was a very slow, arduous process. I really feel for the locals who have to cross these bridges every day.