I'm not sure if this is the best way to do it, but I've been making yogurt for a while now and haven't gotten sick yet. :) It has a great taste, the long fermentation gets rid of all the lactose, and while it's not as thick as yogurt made from pasteurized milk, I think it's more nutritious. (If you want virtually foolproof, thick and creamy yogurt, heat the milk to 180f and let it cool to 110f before stirring in the starter and beginning the fermentation.)
1/2 gallon fresh whole raw milk, preferably from grassfed Jersey cows
1/4-1/2 cup organic whole milk yogurt (store bought, unless you make your own starter), with live active cultures
Whisk the yogurt and milk together, and put into mason jars or a yogurt maker. Place in a dehydrator (or yogurt maker) for 24 hours at 105f-110f.