I was wondering if anybody had any tips on doing a UFO.
I'm really strugling with it.
I'll have a crack at this, as I've been lucky enough to have come across some good advice about this trick, which really helped.
First of all, check out this video KendAlex Kendama UFO Tutorial, けん玉学校 (http://www.youtube.com/watch?v=CuzHBxH6rbw#ws) from Alex Ruisch (Kendalex), it really breaks down the trick into the most important parts, and most of the trick after that is just putting these elements together into one fluid motion. I doubt you will need much more than this video and a lot of practise, but if you feel you're really not getting it, here are two tips.
First of all, slow down. If you are bending your knees right, you will have more than enough time to execute a smooth spin and catch without trying to hammer it at top speed. It's a bit similar to the common problem with Jumping Stick; slow it down, and you'll be able to see the spike come around, or, rather, you'll feel when it's time to make the catch.
Second of all, experiment with the 'launch', by which I mean the moment the ken leaves the tama. Too early, and it'll likely slide off or just spin out. Too late and there'll be no level plane to your UFO, as there's no upward motion keeping things horizontal. Find the middle point, even if you can't catch the ken yet. Just find the point at which the ken rotates smoothly, and try to have that as your launching point.
Thirdly, Void once offered a tip here on a previous post about UFO, and I paraphrase him here: place your free hand on your chest, and align your be-kendama'd hand with this. Use this as a guide when you un-bend your knees to know at what height you should roughly be executing the trick; it's more difficult way up much above or below this height, especially lower.
That's basically the advice I would give to getting down a solid UFO. Such a satisfying trick, well worth the effort.
Good luck!
EDIT: woops, forgot the hyperlink. 'Scuseme.