Given the majority of your riding will be done in the standing position it is important that your controls are suitably adjusted and your body position is correct. Adjusting your weight distribution depending on the surface you are traversing is very important. Sitting in the apex of a turn and on smooth roads is recommended.
The pivot point on a bike is the foot pegs, legs are like extra shock absorbers with arms acting like additional front forks, with both bent. Knees locked into the tank, head forward of your centreline and backside to the rear about an equal amount.
Hip to shoulders are straight. You should be balanced fore and aft and side to side. Look ahead not at your front fender, this will allow you time to react. If your legs burn, lock your knees more to take some load off.
Grip handle bars with index and/or middle finger covering your brake and clutch. Emphasis on keeping the brake lever covered for fast reaction. Don't grip the bar hard, the v from thumb to index finger on each side can maintain control most of the time. Obviously, more grip in bad ruts, etc. Try to keep wrists straight, not cocked up or down.