Like others have said, seat time is the no.1 way to learn. There are an infinite number of variables to contend with in the offroad world, and at high speed, your margin for error decreases exponentially. I've been racing, riding, and driving just about anything with wheels, on and off road, for over 25 years, and there's still more to learn and life lessons to be had.
Having an experienced co-pilot could help you tremendously. They can point out bad habits and teach you new technique. Being humble is key there. Going to raptor events would be a great opportunity for a teaching scenario.
With time, you can start to drive "ahead" of your truck, right now your behind it. Your terrain reading and reactions are way too late. Pre-running helps with that as well, but being able to read the terrain and course at a glance and react to it should become second nature. Start at 40-50% pace and work up to 70-80%. Unless your racing competitively, you should not be driving at 100% pace. This will leave you room for error to correct yourself out of a dangerous situation. Right now, you would driving over 100% of your limits.
The key here is ONLY you can decide what your limits are. Your 70% is going to be different than anyone else here, so don't let others make you think you are going to slow. Your 70% may be someone else's 40% and vise versa.
The raptor is a very capable vehicle in experienced hands, and while instilling confidence in novices, it still has limits, and certain characteristics that can bite you if your not prepared. Learning the limits of your skill and your vehicle's capabilities is a tricky one. Most learn the hard way, and usually end up shiny side down. But I believe that if you learn "your" skill limits first, you can then start to find your vehicle's limits. Sometimes you learn both at the same time, but the goal is to always be one step ahead of your vehicle.
