When you drop her off keep it light/general. I tell my girl, give it your best, have fun, I love you..............
When you are at the meet, remember nearly every spectator has someone they love competing, keep any non postive commentary of other teams/kids to yourself.
For the bag....... water, extra hair stuff (bobbys, pony holders, travel gel, travel hairspray, brush), first aid kit (bandaids, Neosporin, hand lotion, tape, tape
grips if you have gotten that far). Snacks (we don't do nuts, as we have gymmies with nut allergies) that are mess free. Grapes, banana, cheese sticks, crackers, apple slices, egg whites) Change of clothes, for the ride home.
Awards. For us L3 really varied. Top 3-5 usually medals. AA perhaps a trophy or a medal.
For you. Have a note set up on your phone to record scores. Set up a bookmark for meet scores on line (in case they are using that) Cameras, cash, credit card in case you want to buy the sweatshirt or photos.
When its done, praise effort and skill, not scores and placement......... Nice recovery on beam. Your presentation on floor was awesome. All that hard work on bars really showed today.
And seriously its about how your kid does compared to last time, so this is your baseline..................... Every meet is one meet in what will be a journey of whole bunch of meets. Keep perspective.
Breathe and if that fails, drink

(said tongue in cheek, unless you don't have to drive

)