For the most part landscape photography involves photographing stunning vistas under beautiful light with no sign of human intervention whatsoever.
Travel photography is slightly different in that often having people in the picture is the aim. Especially when you want to show your audience the size of something.
No matter whether an object is big or small, when it's printed on a 6" x 4" print it'll look pretty small. A really great way to show people the size of something is to put something instantly recognisable in the picture.
For travel photography often the most convenient 'recognisable' thing is a person. We're all roughly the same height, give a foot or two, and when we see a person in a picture we know straight away how big or small something is.
Take this picture of Dune 45 at beautiful Sossusvlei in Namibia, southern Africa. Now these dunes are up to 300 metres high. Just enormous. And I did a lot of pictures just showing the dunes by themselves but as I was driving out of the park one night I noticed that there were still a few people coming down from the top of the dune.
Now in this particular case, because I wanted to make the dune look big the first thing I did was reach for the telephoto lens. Remember that the wide-angle makes things look wide and spacious and the telephoto makes things look big. So I reached for my telephoto.
The next thing to do was to frame the photo so that the camel tree was in the bottom of the picture. By showing a pretty recognisable plant in the picture you give it a geographic sense of location. Acacias are pretty synonymous with Africa. I also chose to cut off the top of the dune at the top of the frame.
When you don't include the whole object in the picture it invites the viewer to imagine what lies outside the borders. Doing that makes people think that something is really big - which in this case it really is but it helps to heighten that feeling. If I had showed the whole dune you would know where it ended and it wouldn't look as impressive.
The only thing left to do was wait until the people moved down into the frame. I waited until the bottom person was about halfway between the top of the tree and the top of the picture and snapped.
And that's how you show people how big something is in one of your photos. The only other option is to blow the picture up to life size and I don't think my house is big enough!