Another very simple technique in Photography: leading lines. Take photographs of subjects with lines that lead the eye.

A classic example are the parallel railway lines. This one is of the skytrain in Bangkok taken at dusk.

You find lines in roads and on buildings as well. A plain shot is suddenly a better composition for having those leading lines.

 You can try other ideas too. Here are some more great examples and galleries:

The flickr group is great and so are these pictures on Photography tips.