Although this may seem obvious, it's not something everyone realizes they need!
This tool is helpful for remembering:
-What you need
-What you already have
-What you should prioritize looking for
A solid Back Pack can really make or break a convention experience, depending on how much you end up purchasing. I would recommend bringing one no matter what. Not every vendor has bags and carrying your stuff around in hand gets real old, real quick!
More than likely, you will need more than one of these. But even having one full one to start your day off can save you $5-7 right off of the bat, and if the Convention Center permits, you can possibly keep re-filling at a fountain!
Pens & Markers
Chalk these up as some of the essentials to have in that Back Pack of yours. Not only are they handy for marking new purchases off of your checklist, but you never know who you'll run into and when! It's better to be prepared!
File this one under: Professional Con Attendee.
Having a dying phone in this day and age can be stressful, and not having a place to recharge can exasperate that exponentially. Having a backup battery with you is a good way to ensure this never happens to you!
Bringing enough food to last you the whole day is probably an unrealistic expectation, but much like the water bottle, having something with you to start the morning can pay dividends as the day goes on.
I'd strongly recommend:
Comic Book Protection
Having those new books in your Back Pack can make things easier while walking around, but you still want to ensure that they are safe. I would suggest a couple of stiff pieces of cardboard be placed in your Back Pack beforehand so that you can sandwich your books between them and add an extra layer of protection.
Floor Map/Vendor List
Although I am not sure that they hand out physical copies of these at the shows, you can definitely pull one up on your phone or print one out ahead of time.
Having a general idea of the layout and location for your favorite vendors can make walking the Convention Floor a much more enjoyable experience,