One common piece of advice that did not work for me last year in my first couple crits: Stay near the front to avoid the surges on the corners.
That's easier said than done if you have limited experience navigating a tight pack and everyone is fighting for the first 10 spots. For a first crit, I'd recommend hanging further back where people are less agressive about position. You will work harder and there's a better chance of getting dropped or caught behind a wreck, but I think it's safer overall (for you and others). I see too many people freaking out in in the 4/5's when the pack gets tight and there is contact. Freak outs and tensing up turns into wrecks.