The basic of a boomhit is really easy: Strike fast, hard and accurate.
If you want to do one, always try editing, sometimes a mere joint means the difference between a boom and your foot getting stuck betweeen two joints without damage.
And If you want to boom, try to stick your hand/foot as deep in Uke as you can before actually hitting him. ( may sound weird, but that's how Toribash works).
Shook made a guide about boomhits: http://forum.toribash.com/showthread...hlight=boomhit
Enough help?
I hate searching, it always removes the keywords, like i searched how to fight, and it removed the how and the to and gave me a hundred pages of threads containing the word 'fight'. Which was shit.