Speaking of shooting in the summer, the prevailing instinct is to try to stay cool but wearing shorts and a t-shirt but in my experience it's actually better to wear lightweight long sleeve shirts and pants and steering clear of anything cotton. I've seen guys get lobstered pretty good on the arms, legs, and neck from going casual during the match and neglecting sun screen. I have a couple pairs of those lightweight fishing shirts with a hood that I keep up through the match that have proved to be invaluable shooting on exposed ranges in 90+ degree heat. I don't wear anything under the shirt and I was surprised how cool and dry it kept me even on hot days. Cotton t-shirts on the other hand get soaked, stay soaked, and cling to me like a wet blanket while doing little to protect me from sunburn. The pants that I like to wear are like lightweight hiking pants from Wrangler that keep the sun, bugs, dirt, and everything else off my legs as I'm navigating stages. I can say that at the end of the day wearing the full length lightweight clothes I'm tired but I don't feel as worn out and beat down as if I was just wearing shorts and a t-shirt.
As much as I like trail mix, I've had to ease up on it since it doesn't seem to agree with my stomach for whatever reason. I like beef sticks vs. jerky too for a mid-day snack but stay away from the SlimJim shit and dried fruit isn't too bad depending on what it is.
Oh hey, don't forget wet wipes.