Dear Paul,I meditate daily (or more often). Mark Cohen's advice above is very good and is the basis for a fairly common form of Zen meditation based on breathing which I often use. You can also help concentrate on the breathing and help dispel intruding thoughts with a simple one, two, three...ten counting first on the breathing in and then the breathing out.
Try a web search also on Charlotte Joko Beck, a well known author on Zen meditation and teacher. Many of her lectures on meditation have been published and may be available online.
Hope this helps a bit
mooman (also greatly saddened by George's passing)