Check What Creators are Going - I had an embarrassing moment at Wondercon where sadly I was having a conversation with Joe Casey and Josh without realizing that Casey was indeed the one who wrote Godland a book that I thoroughly enjoyed.  Later I realized this and felt like a rather big idiot.  Taking a moment to look over who is at the con or events you are going to and correlating it with your bookshelf is a good idea.

Check your Car - If you're driving your car have it checked before hand.  I was burned on this in the past and had to scramble for alternative transportation.  I got lucky, you on the other hand may not be.  Do yourself a favor and have your car checked before hand or get a oil change to see if anything wrong with your car pops up.  Would you rather pay some money before hand to have a safe and reliable form of transportation OR would you rather miss the whole thing?

Things to Bring:

This is where the list that you created earlier comes in handy.  Things I always take to a con are as follows...

Entertainment - I always take my DS, PSP, and eReader with me to all the Cons I go to.  There will be times when you're waiting to see a creator or even to get onto the show room floor.  Having something to pass the time that won't weigh you down too much will make things go by much faster.

Water, Snacks, Food - Con food and water is over priced, there is no getting around this fact.  Currently a con that resides in my home state went from twice a year to once a year because the Showplace demanded that creators and vendors purchase food and water at the convention center.  This resulted in the Con only being once a year since creators and the like couldn't afford it twice a year with it being as small as it was.  Taking snacks and water will therefore bring down how much you spend on these things and leaving you more money to spend on cool things at the con.  I even found that Slim Fast works for me in "eating" really cheap for a con.

Comics to sign - Signatures are a neat thing to have.  Yes, you can sell them at a later date, but you may end up with a special story to go along with the autograph.  An added item to this would be some permanent markers.  Most creators have them, but there may be the time that one runs out of ink and you happen to have an extra.  Most backpacks and such have the space for pens anyways.

iPod and Tunes - You may wonder why this is under entertainment and that it seems stupid to mention, but I've been to a con where I forgot my iPod (remember that list I mentioned earlier) and was less focused on what I was doing.  I use my iPod as a tool to keep my concentration on certain tasks when I'm in buying mode or tracking something down.  The con floor is a noisy place and having something to drown it all out is nice.  I usually am a man on a mission at a comic con, sadly I get easily distracted at the same time.

A Good Bag(s) - Carrying a metric ton of swag can leave a little bit of strain on your back.  At Wondercon I took a simple Timbuk2 messenger bag.  I will go on record as saying that it probably wasn't the best choice.  Within 30 minutes of hitting the floor I bought The Complete Mad Man and the first 5 volumes of Nexus.  I spent hours carrying these books around and it was a killer on my back.  I would stay away from a messenger bags altogether in my opinion.  I also have a simple Eddie Bauer backpack, which I have used to carry as much stuff with less pain and suffering.  More backpacks tend to have a spot to fit a water bottle as well.  With a messenger bag you're lucky if it has one, if not I don't suggest doing what I did and using a carabiner to attach a water bottle.  This may be more of a problem for guys, but I found that I "tagged" myself more times than I would have liked.  Also if you are taking a plane having an extra swag bag you can carry on is not a bad idea.  I saved myself an extra 90 dollars having a carryon for my swag.

Cash - This also sounds like a stupid thing to mention, of course you're going to want to bring cash.  The problem is that maybe you don't want to grab all of what you want to spend and use a credit card as backup.  Here's a little dirty underhanded Accounting trick for you, if you take cash most vendors will not charge you tax.  Also a lot of vendors don't take credit cards so if you do need to get cash you'll be stuck spending an extra 2-5 dollars depending on charges with your bank and the ATM.  That could be a comic you could pick up but instead you screwed yourself getting more money.  When you could have had it on you in the first place.  You may also want to carry your wallet or cash in your front pocket... you know if you're like me and are a paranoid type.

A Girlfriend or Friend - I know this sounds crazy and a little silly, it is, but having someone else that can help you in your Con adventure the better.  I've done cons with girlfriends, friends, and solo.  It's always better with a girlfriend or friend, they share interests (sometimes) with you and that's why their there.  Yes I'm also not above using a girlfriend and/or friend to help me carry things. Also it makes less trips back to your hotel room or car, meaning more floor time.  Although something can be said for going solo and doing your own thing.  This would of course be the most optional of all the things on my list... sorry girlfriends, boyfriends and best friends of comic nerds everywhere sometimes we need our alone time with thousands of our kind.

Camera, chargers, and other misc. items - Having all the necessary chargers for your gadgets and such will come in handy.  You don't have to carry everything to the show room floor, but you don't want to run out of juice over the weekend.  Also having a camera means you can get all of the moments you want to remember.  Once again this may be a no brainer to some people.  Don't forget that list and schedule you made, it would be for nothing if you did.  Also just because it's not in my article doesn't mean there isn't something else you think of to bring.