Place the 2 bottles of water into your freezer the night before the all day concert. This is so that they will stay cold the majority of the all day concert with out needing a cooler to store them in.
Gather all of the items listed on the things that you will need list for the all day concert and place them on a table. This will make packing for an all day concert quick and easy.
Place the frozen water bottles and food in the bottom of the large backpack. You will not need these items when you first arrive at the all day concert so keeping them at the bottom will keep them out of the way.
Place the first aid kit, trash bag, sunscreen, notepad and ink pen, baby wipes, and hand towel into the backpack next for the all day concert. You do not know when the need may arise for these items so placing them here makes them more accesible.
Put the blanket and your sunglasses in the backpack last. These will be the items that you will need to take out of the bag as soon as you arrive at the all day concert so do not bury them.