yeah, learning the attack position is key. relaxed but purposful arms and legs to soak up the bumps but hold your line. look as fsr ahead as you can. if you're all puckered up and stiff, staring at uour front wheel, thats when you get bucked. heels-down will naturally shift your weight back (assume you're out of the saddle). only when it's REALLY steep to you need to worry about getting behind the saddle, esp with today's slack geometry and bigger wheels. you really have to work hard to endo a modern 29er.
youtube has some good stuff, and 2x's advice above is pretty good. but the #1 theing to make you get better is to ride with others. hard to say fuckit when it means holding up the group and humbling yourself. you'll be surprised what you can do when you have company to passively push you.
as far as Brushy, it's a great place to learn. easily navigable, and a nice mix of smooth twisty, and rocky chunk you find around here. rode it yesterday, actually. a pack of 30-somethings gawking at the Basket drop called me 'sir' as they apologized and scooted out of the way for me to hit it. Sir. me. jfc.
anyway, based on prior Stravulations, over the last couple days, I did about 9 miles at Brushy (350' of climbing), and another 11 miles today at bcgb (>1600' of climbing). combined with a 2-mile (w/>200') run on friday to give my newly-arthritic thumb/wrist a break, I am freakin toast, right now. good start to the new year, tho.