^^^ These posts. Especially as regards getting into position and on target quickly! That's my weakness - I'm older than most PRS competitors with a few mobility challenges; I tend to avoid positional practice because it's not easy and can be uncomfortable. It costs me bigtime in matches. Watching video of myself in a match is almost painful because I'm so slow. So - practice getting into a stable position, getting on target, closing/cycling bolt, and trigger pull on barricades, barrels (on end, across, end-to-end), tank traps, etc. By far, this is the best kind of practice you can do if you are confident in your dope. Remember, though, It's far better to fire half of possible shots in a stage and hit them than fire all of them and miss all but a couple.
Do you have a ballistic calculator? If not, Get One. You can research them here on SH. I have tried several and stay with Strelok Pro - I think it's currently about $13 on iPhone app store. You have already collected actual dope; you can use it to "true" Strelok's (or other calculators') calculated elevations.
When you get to the match and get started, just accept you'll be nervous and do silly things. Sheesh, I've been competing in one shooting sport or another for many decades and still get flustered. I shot a match this past weekend which had a stage where shooters started prone, mag in, bolt back, safety on, rifle shouldered on rear bag of choice. My shooting buddies - one of whom posted above - will tell you I seem to be jinxed on this stage; I've done something stupid on it 4 matches straight, including a ND (finger rotated around slamming the bolt home on first shot and hit trigger) - immediate match DQ. Yesterday, I was sure I was ready to break the spell. Rifle up, cheek welded, timer beeps. Close bolt... won't close. Drop mag, reinsert, try again. Won't close. I'm still on the rifle when RO mutters "chamber flag." I didn't remove the chamber flag.
Biggest mistake I made in my first match was leaving scope magnification turned way up. This resulted in my not being able to find targets in the scope and/or firing on the wrong target. 12-15x magnification is plenty.
Stay hydrated and bring enough energy food to get you through the match. Sun block and bug spray. It's fine to tell your squad mates you're new and ask questions. Be sure to let the ROs know as well. Be absolutely sure to practice perfect muzzle discipline at all times.
Have fun. Be safe.