I have made several over the years.Here are few things I have learned. Don't skimp on firebox size. It is easier to damp a big fire than to feed a little one. Line the bottom of your smoke chamber with fire brick or stone, it is a cheap way to retain heat. Build lots of draft into your smoker, again, it's easier to damp off than to try to get a little flue to draw.Don't make a smoker so dang big that you won't use it either. Rarely do you smoke a whole hog. It is too hard to get one of those monsters up to heat and keep it there. My most useful smoker can smoke about 90 pounds of meat at a time but is not so big that it never gets used.