1 | Compose with the light source at the edge of the frame. Placing the light at the edge of your composition or just outside visible edge of the frame increases the likelihood of flaring and also increases the amount of flare.
2 | Lose the lens hood. Lens hoods are designed to reduce the amount of stray light that enters the lens, thus reducing the amount of flare in your shot. Removing the lens hood increases the probability and amount of lens flare in your photos.
3 | Use a wide-angle lens. Wide- and ultra-wide lenses tend to flare more easily due to the fact that stray light is more difficult to block (the light is coming at a steeper or more obtuse angle than with a longer lens). The wide curving optics also reflect light to a greater extent, creating more flare. Note, however, that more expensive wide-angle lenses often have more and better optical coatings to help reduce lens flare.
4 | Shoot wide open. Using a wider aperture allows more light into the lens, which in turn, increases the amount of stray light that's available to be reflected amongst the lens elements to create flare. Conversely, using a smaller aperture focuses the light coming in from the lens toward the sensor in a tighter pattern, controlling it better and reducing errant light rays.
5 | Use older and/or inexpensive lenses. Since film doesn't reflect any light back into the lens barrel, older film lenses usually don't have coated rear elements. The shiny glass filters in front of digital sensors reflects light and can cause flare with older lenses. Inexpensive lenses also tend to have coatings that are less effective at reducing flare than more expensive lenses.
6 | Use a UV filter. UV filters (especially inexpensive ones) are notorious for exacerbating lens flare. You can use this to your advantage.
When adding lens flare as an effect to your images, as I mentioned earlier, photographs tend to have reduced contrast and color saturation. So, these types of images often need to be post processed to achieve the best results. At the very least, increasing the contrast using curves or levels in your software is a good place to start. You can also boost the vibrance and/or saturation to bring up the colors. When using Adobe Camera RAW or Lightroom, I find that the Clarity slider works especially well to help bring out some definition in the photograph.