For me I'm using the Deep Relaxed as explained by JP. So far what I've read I often see pucker, curl tongue, and tongue block mentioned. The deep relaxed method as I see it now is not pucker. It's actual lip block for single notes. Blocking the neighbour holes with the inside fleshy part of your lower lip. I've been playing about a month now and that what I use. Eventually I want to try to add tongue blocking. I believe using those 2 methods will co-exist nicely and allow a lot of nice gimmicks on your playing.
Tip I can give additionally. The part 'relax' in the deep relaxed really means relax your mouth and lips. I'm discovering the more relaxed I try to do that without fearing I will hit several notes instead of just one It will actually just be one. Won't come straight away, but once you discover that with this method you can really appreciate it. Pucker method as I see it now requires more muscle activity then DRE.
Anyways, my 2.5 cents after a month's of playing!
Keep on Harpin'!