Here are some of my tips for TechEd attendees updated for 2013.
Do not to pack too many clothes. You can get free T-shirts from most vendors and they usually have incentives for wearing their shirt on the Expo Floor. You will not have time to wear all the extra clothes if you bring them. You will have room in your bag to take home all the T-shirts you will get.
Bring comfortable shoes (not new shoes) for all the walking you will have to do to get to sessions and meals (breakfast and lunch) and maybe back to your hotel.
You will most likely get a backpack as a TechEd Attendee so unless you really like yours or it is a road warrior type or laptop bag, one is not needed.
Bring your cell phone charger and/or power strip. There should be outlets available in sessions and powerstrips in the Alumni Lounge (For past attendees only).
Try to arrive early for breakfast and lunch. Lines can be long but they move quickly. There are separate serving stations for pre-registered dietary needs (Vegetarian, Indian Vegetarian, Halaal, Kosher).
Plan to arrive for sessions early. Rooms can fill up for some of the more popular speakers and topics. Try to attend the second session of a topic if there is one available. Use the Schedule Builder to know what will be available. If you are above a 101 level skip those sessions and attend the ones that will be more beneficial to you and your company. Also add multiple sessions to the same timeslot on your schedule, it can help if a session is full and there is only that one for the entire show.
If you really want to attend the early morning sessions(8:30 am), try not to stay up too late at night. Keep in mind most sessions will be recorded and available later for attendees to download after the conference.
Get to registration early with your final confirmation email and Government Issued ID. There is a self-checkin that was really helpful.
Do NOT lose your badge. This is needed to get into sessions, events and will be scanned by the vendors on the Expo Floor so they can contact you after the show.(it's a business card without walking around with 500 cards).
Use the water bottle provided. There are usually water fountains or water dispensers everywhere. Water will keep you hydrated but do not overdo it. Bathroom lines can be long.