Chewnie, I'd say that the easiest is DILD, but that's just my opinion. I would try all of them though and then see what's easiest for you. I myself have a pretty good success rate with DILDs, but I try other techniques just for fun. I think it's good to have a mastery of a few different techniques so that you can use them in different situations depending how tired you are, how fast you want to go to sleep, how long you're going to sleep, etc.

But again, if you're still struggling just to have LDs, then I would suggest trying the DILD technique untill you're getting them at least 4-5 times a week. Then I would venture out and try other techniques, it's fun!

Good luck