Excuse the rather long post and I hope all this helps you out.
Once the session builder goes online you will often find that you have several sessions that occur at the same time. Don't worry about only picking one choose both or more if your interested in the topics being covered. It not only help you plan out what your going to focus on but it also helps out the conference organizers plan out the room size, and if they get enough they may add in repeat sessions. Signing up for a session does commit you to going to the session and the signup is not a first come first served.
I spend a bit of time on this and I do review my session list several times before the conference starts. When I get to the conference on Sunday I take my conference guide and highlight my sessions, and also find myself reviewing my list every morning (and sometime several times a day). Be prepared to change up at last minute, you may have gone to a session earlier in the week and got very excited about what you heard and now want to know more so change it up. There is a lot of content so try to make the most of it for the best experience possible.
Booking extra sessions not only in case a the session is full, but you may get into a session and find out it was not for you, so you can get up and go to another one, but if you go and are not sure it is best to sit nearer to the door. One other item about booking extra, is the sessions are recorded and available online, usually within 24 hrs, so you can watch the ones you decided not to attend later.
The New Orleans conference center is a large one and there is a lot of walking involved. So getting to know the conference layout and where your sessions is being held is important. If you can, register on Sunday and check out the place so you know where everything is. This will help as when you have session at one end of conference and next session is 3rd floor at the other end, you will want to start walking that way soon as you can, sometimes the halls can get crowded and it can take what seems like 10-15 min to get from one end to other.
I always get in to register on the Sunday so I can also take the time to do a few Hands on Labs (these will be listed in the Session catalog when it goes live), and check out whats new before I hear the talks.
No one has mentioned if this is going to be one again this year, but last year they had a few TechEd 101 sessions on the Sunday, one of my colleagues went last year and really enjoyed it and got some useful tips .