Very often, you can use doorways, windows, trees, plants, rocks or other elements as frames within your photo.
This is a very good way of guiding the attention of the viewer to the main element(s) of the image.
Again, this works best with uncluttered pictures.
Windows in a watch tower of the Great Wall (China) provide a nice frame for the scenery.
Humayun’s tomb (India) seen through a doorway.
Mausoleum of the Aga Khan seen in the distance, framed by plants.
A doorway in Nefta, Tunisia. The figures in the background help to provide a sense of size and make the image more lively.
The dimishing size of the doorways and the difference in brightness also give this picture a sense of depth.