damn where to start. First and foremost make sure you bring enough cash to cover everything: gate fee, pit pass, classes, ama membership all that right there is gonna be over a hundred bucks. Make sure your bike is READY for the race. do all the maintenance on it a couple nights before and if your gonna change anything such as handlebars suspension setting even tires do it in the middle of the week cause you could end up hating whatver change you made and it will mess you up the whole time. As far as maintenance check everything, make sure the bolts are tight, change you oil, clean your air filter, tighten and lube the chain, and please wash the bike; i hate seeing people roll up to races with dirty bikes. Put a new spark plug in it. Make sure your bike is structurally in good shape check for cracks in your frame make sure you dont have any play in the suspension linkage if you do it will definetly compromise your handling.
Make sure you get a good night sleep before the race, dont do the tune-up the night before the race. You don't know how many people I see sitting in line or at the the yawning, your gonna do it anyway because your nervous but dont let it be because you didnt get good sleep. Thats the number one race killer.
On race day leave early and get there early so you get a good spot in the pits or else youll walk miles all day just to get places. Another good reason to get there early is so you dont have to wait in line long for sign ups. If you get there late your gonna be waiting in line for a while then have to rush around just to make it to the gate for practice on time.
Bring spares: bring spare spark plugs (they are like having gold with you for two strokes), if you change your own tires bring spare tubes, make sure you have enough gas you will use more than you think, bring some oil with you and chain lube, bring spare levers and perches, bring a nut and bolt kit, bring enough tools to be able to fix anything that will get you back in the race, and bring wire tires it will make or break your race day with some stuff.
Bring friends, it gets boring sitting around. Your gonna be there between 8 and 10 hours so you might as well bring people with you it'll make it funner and the time go by faster. Make sure your on top of the race order and what race they're on so that you dont miss your moto or almost miss it. if you dont have a tear off kit get one and get tear off for you goggles, you will regret it if you dont. A lot of people dont get them and take off their goggles and get DQ'd from the race. Bring a cooler with some food and drinks. Bring chairs for everyone. If you have a pop up tent bring one. Dont have your gear on when you roll up to the track in your truck its such a newbie move.
Pracitce some starts, your gonna be nervous as hell on your first start so at least get down what you have to do. Don't let other people on the line intimidate you, whats gonna make you nervous is being right next to people and hearing everyone elses bikes. Watch some starts and see how they go down. Look to see how it works with the guy holding the board or if they have lights. Look to see if the guy who drops the gate is consistent with how long he waits to drop the gate from the time the board goes sideways. Some will screw with you and wait a while for some gates and short for others, but some guys are completely predictable and drop every gate in the same amount of time.
Well its a lot of stuff but you will get into a routine quickly and dont be nervous about going.