Guided meditations are very helpful for anyone who has difficulty visualizing and/or clearing their mind, which are two of the primary ways of achieving a meditative state.  I really like chakra or aura-cleansing meditations and recently stumbled across this Aura Meditation by Kathy Rose that is probably the best I've ever encountered.  She has a knack for visual language which, again, is very helpful for those who have trouble creating mental imagery themselves.  In the first video, Kathy explains how an aura meditation is helpful and in the second she guides you through the meditation itself, in which you will visualize yourself filling up with sparkling-white healing light.

Aura Meditation Part One - Introduction
Aura Meditation Part Two - Experience

    If you are one of those folks who doesn't visualize easily, or if you're just in a funk and are having difficulty concentrating on a guided meditation, I also recommend the following, which provides you with both visual and auditory stimulation that will calm and balance you.  For this one, just gaze into the pulsing, changing mandala images as you listen to the healing sounds (I hesitate to call these sounds music as the video's title does, but still). ;)

[To access comments/commenting you may need to click on the title of this entry, then scroll down to the bottom of the page.  I'd love to hear your thoughts on these meditations, or suggestions for others!]