Well, let's see. Payment? Cash is always good. And so is debit and credit. How long to stay? Be prepared to stay all day. What time to arrive? Early. The parking lot fills up fast. How late to stay? What kind of endurance do you have? Food? There should be restaurants in the area to help you take care of eating. But most of all just be prepared to be awestruck. You won't believe your eyes. The models and variety of models on display will truly boggle the mind. And vendors. Geez, the vendors. If it's an item that relates to our hobby, it will be available from a vendor. I hope you're driving a station wagon or an SUV because you're gonna be buying some kits for your stash.

Well, you probably want to be there somewhere around nine. I'd bring cash, some vendors will take checks or credit but they always take cash! Our show is five bucks general admission or ten for the first five models plus a dollar for every additional model past five so you probably don't want to write a check for that amount. 

Also our show is in a civic center with a cement floor so you want to wear comfortable shoes and you might want to sit down every now and then. With a show in a hotel you probably would have more leeway on what you wear here but a cement floor will kill your feet after a few hours. 

If you're entering multiple models you might want to see if you can download the entry forms off the club website and fill them out at home. I think you said you only have the one diorama so they shouldn't be an issue. 

Personally I pay my admission, enter my models and then buy some raffle tickets and then look though the vendors stuff. If there's anything I have to have and only a handful of kits I'll buy it right away before someone else does. Then I wander around and look at the models. The tables will slowly fill up as people bring entries in up to noon or so. Then as the show closes I'll hit the vendors again, a lot of them will cut deals at the eleventh hour to keep from loading stuff on trucks and hauling it back home. Also you might try 'bundling' - ask the guy if he'll take fifty bucks for three twenty dollar kits. Some vendors will, some won't - just be polite and it can't hurt to ask. 

Also I always play the raffle table. I've always made my money back, thirty dollars of raffle tickets has always gotten me a good thirty dollar kit and a bunch of crappy kits. Sometimes I hit the jackpot and end up walking away with way more than I paid for. Of course you have no idea what you're going to get so if you only build US armour you very well could end up with a couple of German tanks. You might try swapping with someone though- 'would you be interested in trading this Tiger for the Sherman you won?' Of course you can look for tell-tale signs of someone who looks unhappy or miffed by what they won or a guy wearing a Ford hat winning a Camero for a good bet here. 

Most places will allow you to bring some food in so you might bring a candy bar and a soda or bottled water. At our show there's a Hardee's / Carls Jr. within a one-two minute drive. And a small strip mall with an excellent Szenchen Chinese resturant, a Subway, and a good steakhouse within a five-ten minute drive.  

Volunteer to help judge even if you have never done it before.  Judging gives you an opportunity to closely examine others work and learn.  ‘Oh, I see how he did that. I’ll try that on my next build!’

You will be teamed with a more experienced judge and he will point out what is looked for and will help you avoid the typical pitfalls which eliminate many entries in the first cut

What would be the procedure for volunteering? Also, is it 10$ per model for the first five of is it for all? If it is for all I may have more, I was only going to enter one as 50$ seemed too much to me for entering.

Ask at registration to point you to the head judge. Tell him you want to help and he'll tell you when the judges meeting is. Specific club rules will be explained there. You will be teamed up with several others but cannot judge any class in which you are entered. By that I mean if you enterred only 1/72 aircraft, you may judge any other scale. Or you may want to try your hand at armor or cars. Basic skills, not accuracy wil most likely determine the finalists. You don't have to be an expert of the subject. IPMS recommends that accuracy not be a prime factor in judging. 

If you want to shop for bargains , arrive early. If that's not an issue, you can arrive later. Cash is good across the board, since some dealers are simply clearing their stash. The club probably will not be able to take debit/credit for registration, but a check should do. As mentioned, if the club website has their forms, download them. If possible, fill them out in the computer to make life easier for the judges. If not, use your absolute best handwriting...block printing is best. 

Don't over over your models, especially during judging. If you see something you really like, seek out the builder if you can and ask questions. Most of us are happy to share. Ignore the guy who is pontificating that the bue on this Corsair is off by a shade or that a stock Camaro in 1979 did not come in this shade of green. 

Lastly, have fun.