Pretty much this some great advice in there.
Also contrary to a lot of people in this thread make sure your clothes aren't too tight. You need at least 4cm of material that can be pulled out and measure on your arms and 8cm from your thighs downwards including at the top of your boot. However, as long as you're not wearing a speed suit this doesn't matter under USASA level usually, but something to watch out for.
Try and stay as compact as you can in the air and during the course to get as much speed as possible.
Remember intentional contact, putting your poles between their legs, pulling or pushing them is all illegal however you are allowed to lean on them and hit them with your hips.
Make sure you do a good inspection of the course looking at the features figuring out how much speed you need, which ones you need to absorb which ones you need to pop. Where the course is wide enough to pass, the line you need if you can't see the next gate after take off and what direction you need off the jumps.
If you're not confident in the training, watch a few of the more experienced racers and how they take the course. After the first run or so you can even ask them if you can follow them down the course and do as they do.
Overall just give it a go and have fun. What race is it?