-- Plan to walk a lot; comfortable shoes; carry as little as possible -- maybe some jerky or a bag of nuts for quick refuel. If you have a close hotel, drop off stuff and pick up other stuff as you need to.
-- Expect that you might spend a lot of time browsing all the booths in the exhibit hall; you can, and probably should, spend a couple hours on this; this exhibit hall is like no other; you can also sit down and demo games at a lot of the booths, if that appeals to you
-- I'd avoid buying food in the convention center. It isn't a good value/quality proposition. Some people like to use the food trucks just outside the building to the east. Personally, I don't like the lines there. I prefer to walk a few blocks away to Jimmy Johns, Chipotle, etc. Or even Buffalo Wild Wings, etc., if you want to sit down. This will be easy if you are even 3 blocks from the Convention. The exhibit hall closes at 6pm. There will be a food rush at that time. If possible, try to head to food by 5:30
--There are things going on in the attached hotels, too. Some are scheduled events. If you need downtime, consider the film festivals in the Westin hotel across the street to the north. This is usually on the floor right above ground level. You can just walk in and sit down and rest up while you watch a fan made film. If the film is a dud, get up and go.
--Obvious, but think about what you don't want to miss and plan around that. Costume Contest? True Dungeon? Both of these are big league and relatively hard to get elsewhere. Possibly better use of your limited Convention time than a board game you play at home.
--Some games work better at a Convention than at home. Some don't. Do you like "Are You a Werewolf?" or "Diplomacy"? Things like this will probably be far better at the Convention because you are playing with a large number of strangers. Do you like "RoboRally"? GenCon has an event where you play programmed actual robots to execute your orders. Consider these kinds of special events which you can't get elsewhere.
-- Event tickets and hotel housing are competitive. Plan to be ready to go at the minute the portal opens. Hotel has already happened this year, of course. Events go on sale this Sunday. Before that happens, pick what you want and put them in your "wishlist" so that you can try to process them in minute #1.
-- Try something you haven't tried before.
-- Have fun. Don't overschedule every single minute.