In my opinion, and many years of experience, there are many preparations that definitely deserve consideration when taking a ride.
Swampy mentioned one of them, double wrapping your lanyard so you don't go down very far if you gaff out.
And with all due respect to Swampy, the seriously violent rides usually occur when you're catching whatever it is you're dropping. Push off rides are generally mild compared to catching rides.
It is your ability to triangulate with enough power to move as one with the wood until the ride is over that ensures your success when " riding the bull ".
If I know that some serious rides are coming, it is one of the few times I'll use a long chainsaw lanyard so I can drop my saw and use both my hands and push as hard as I can against the catching wood or trunk as it tries to beat me to death whipping back and forth. Getting the right length on your lanyard so that you can straight arm the wood during the ride helps alot.
If I know that the ride ahead of me is going to be truly nasty ( big wood catching on a block ) I'll take the unusual step of standing on just one gaff and using my other leg bent infront of me to aid both arms in pushing against the tree when the load hits and the ride starts.
Because some catching situations demand the load drop to be minimized to avoid targets, dropping your chainsaw on it's lanyard in the vicinity of the potential load contact with the catching trunk can result in a smooshed ms440, not a good thing. To avoid this problem I have learned to leave just enough holding wood ( even in bigwood ) that I can attach my chainsaw to my belt, then finish the cut with my handsaw and drop it to the ground in the second or so before the ride starts.
It is always a good idea to have your bodyline around the tree in addition to your lanyard, it will provide you a quick way down to the ground in the event that something goes wrong and you're injured.
In my mind, blocking down bigwood is very serious business that should only be attempted by true pro's that know the risks involved and how to mitigate the danger inherent in doing it.
I've seen quite a few climbers get in over their heads doing it and get beaten to a bloody pulp.
Use a crane if you can, otherwise work smart and work safe.
jomoco