How do I get a VAT refund ?

When I bought my HP mini notebook here in Bangkok last December, 2010 at Pantip Plaza, I didn't have any idea about claiming a VAT refund here in Bangkok. Lately, I have found out the process and the things that I needed to know through my experience living here in Thailand, as a tourist. I had several researches online, too. As this would help me a lot in the future when we've decided to buy