Lately, I've been trying to do WILDS. the last time I did, I header a sound for the first time, a low sound, just like someone is mowing the lawn a few houses away.
Just like NrElAx said, just try to get asleep, but keep something in the back of your head that keeps you conscious.
I've found that concetrating on breathing isn't really my thing, but as I got nothing else, I tend to switch allot and then think about all this crap, so I haven't really got a succesive WILD, but I'll keep trying
(perhaps I'll turn my fan on next time)