It's lots of peoples first meet. These are items you need to bring:
For Lifting:
Attempts - Have your plan all laid out. It's better to have someone with your numbers so it's one less thing you have to think about.
Singlet (I forgot mine for my last meet) or gear if you are one of the 7 geared lifters left in the world
Shoes - Squat and deadlift shoes. If they are different
Socks - If you are a sweaty person like me, bring a pair for each squat, bench and deadlift
T shirt - At least one for each lift. If your meet is in the summer, maybe 2 for each lift.
Underwear - Bring a change for after you're done lifting. Swamp ass looks good on no one
Belt - Large things seem to be the easiest to forget
Wraps - Wrist and knee wraps. if you have extra. Bring them. Someone is going to forget. Remember this sport is NOT about you
Mouth guard - I'm a big fan of them. If you have one, bring it. If you don't, get one.
For when you're not lifting:
Baby wipes - Legit. Especially if you are cutting weight. Your guts will probably not be right all day. This will keep everything more tidy. Paul Oneid I'm looking at you.
Imodium - Also, if you are cutting weight. Helps you not shit your pants and put that water weight back on.
Sandals - For between lifts. If there is a big meet it's nice to not have shoes on for a while if you are going to e an hour or so between attempts
Food and Water - I personally hate water and pretty much only at meets and when I'm being cheap eating at restaurants. But it's key during a meet to keep your energy up. For the food, keep it simple. Donuts at meets are a stupid idea. Donuts in a gym setting is fucking dumb all together. Stick to food you have been eating for the last couple weeks before the meet. Chicken and rice or salads are pretty good choices.
There is a lot more things that you can do for a meet. But, if you start with all these, you will start the meet off on the right foot!!!