I've never had any luck at all with pendulums (or tarot cards, for that matter), but I have had excellent results with the "hotter or colder" thing. I don't actually feel physically hotter or colder, but it's like that game you play as a kid, where someone hides something and then you go looking for it and they say "Getting warmer... getting warmer... cooler..." and so on until you zero in on it.
Yes, I am clairsentient, for what it's worth.
I might try the "future self" thing, though. There are a few things I'd be very interested to hear from my future self... Like, say, winning lottery numbers....
(Not that I EVER know what the winning lottery numbers were or are; perhaps I should start to take note and write them down so that in the future I'll know and be able to ask myself? Tee hee! Possibilities are amusing