These guys are all giving great advice. Some decent fitness goes a long way. Especially preventing injuries. Mostly though, I think a riding class and lots of time on the bike will get you all set. I've been riding since I was a kid and still fight bad habits.
I think once you are able to trust the bike and understand its limits it will help a lot. I pretty much stand the whole time and feel less fatigued than if I was sitting. You learn to use the forces acting on you to help you relax.
As far as falling forward, if it makes you feel any better, much of the time I'm on the gas, I can look at my front number plate. I'm 6'4".
I'm 6'2", so we are close.
With what everyone else has said about fitness and being in shape.
I AGREE completely, however, I have spent more time in a gym than I really ever want to again. My username is the MOS I had in the ARMY, fitness was part of life while I was in. I'm out now, if I am not having fun I'm not doing it any longer.
I have gained weight from being 215lbs and cut, in shape running 7 minute miles and doing the never ending push-ups and sit-ups. Now, I'm fat and out of shape. The issue is how do I have fun and get back into shape?
Gym membership, not happening.
I work outside a lot, so I may be fat, but I have stamina that could walk circles around many of these so called "In-shape" people. Been there done that, muscle heads that can lift but can't work a full day without being torn down at the end. While I'm ready to go have a beer and play golf or whatever else.
gasgasxc: Your comment about "Its the same group that only rides together and you are never invited along.
It isn't because they are unfriendly pricks.
To them out of shape egotistical wanna be badasses are their biggest fear and worse nightmare on the mountain."
These are the people I don't associate with anyways. Why? There ego is just as big as the next guy yet they forgot something; at one point in time they also started somewhere and they also had the gear and bling. I'm all for riding with people that are about the same skill level, but there is a difference in belittling new riders and helping push new riders.
Example: Guys I rode with yesterday B riders, good guys. Yet they were happy to have someone new to ride with and took the time to show some lines and pointers as to how to take some of the rougher sections of the trails. They also understand that riders get better with time and experience.
Me personally, I would rather ride with people better than me. Give you that extra push to learn more and do better. But it takes a special person to care enough to wait from time to time for them to catch up. Seriously, how bad is it to stop for 1-2 minutes every 4-5 miles for someone to catch up to you. Grab a drink of water, smoke break, piss break.......The slow guy it sucks, they just keep moving.