I can’t remember where I picked up this tip - it was a while ago when I read it - but it’s certainly been helping me reduce the amount of spending I do on unessential luxuries (gadgets mostly). The essence of the tip is:

When you get the urge to buy something, don’t do it straight-off. Instead, write down what it is you want, along with the price on a post-it note or similar. Stick the note somewhere prominent (like the fridge door). Look at the note once a day, for 30 days. Also put any loose change/spare cash into a collection jar. If, after 30 days, you still want the item as badly as when you first got the urge, then treat yourself if you can easily afford it (use the money in the collection jar to help). Otherwise bin the note and keep your money.

This bit of advice has probably saved me about £1000 in the last few months when I’ve had urges to upgrade my camera, iPod and DVD player. It is similar in concept to Steve Pavlina’s 30-Day theory which I have also applied successfully to other areas of my financial life (for example, taking my own lunch to work everyday instead of hitting the sandwich shop… saving approx £4 a day). Try it for a while and see how you get on.