1) Start by lighting a white candle on your altar if this is not part of your regular practice. Dim the lights. Sit in your meditative state. Completely relax yourself.
2) Direct your gaze to the burning candle. Do not stare intently, but face the candle with your eyes open. Let your focus soften.
3) Let the image of the candle fill your thoughts. Focus solely on the candle and stay in the moment.
4) Do not strain your eyes. If they are tired, close them, but visualize the candle in your mind. If visualization is difficult, alternate between opening your eyes and studying the candle, and then closing your eyes and re-creating the picture in your mind. This will help build your visualization skills. Do not worry if you have difficulty holding the image. Hold the idea of the candle in your mind. Relaxation with focus is more important than visual skills at this point.
5) Do this meditation for a few minutes at first and build to longer intervals. When done, close your eyes, rest and relax.
*** You can substitute any object for the candle, re-creating it on the screen of your mind.***