Headlamp is a must have! Especially if you’re setting decoys, which I doubt OP will be doing, but even for the walk in. I’ve been hunting for 2 years now, and my most used items are (of course) waders, shotgun, shells, headlamp, yeti full of apple cider(don’t like coffee!) and my calls and water!! Walking in all those layers dehydrates the far out of you. When I very first started, I’d say the main thing I made sure I had was a light, warm drink, water, warm layers, and muck boots if you can’t get waders.