The most basic part of attending is the planning process. Find out as much as possible about the conference and the location prior to attending. Where does it happen? How will you get there? How much time difference will you have to handle? Where to stay? What's around? Is there a chance to contribute? Are my favorite vendors there? Does someone else is planning going there? Are there any other travel related things to keep in mind (e.g. power adapters)? The more you know, the better and safer your travel will be because you don't have a feeling of uncertainty which prevents you from enjoying the time.
Bring down your todo-list to zero before!
There is one thing I can tell you: You will not have a single valuable moment at a conference as an attendee, if you are always trying to get things fixed from remote. If your project doesn't allow you to leave. Stay! Skip the conference! Being able to go implies, you have taken every action before to hand over open tasks to colleagues or closed them yourself. You could of course be reachable. Nobody is forcing you to shut down the connections to the home base. Simply make sure you don't have any significant problems left to handle.
Get clear on what you want!
The second step is to get clear on what you want. Set yourself clear goals that motivate and inspire you to attend the conference. Now look at the schedule. They get published (even partly) quite early and you can get a good impression about the content that you have to expect. Most conferences offer far too much stuff to cover. So you have to find your basic stream/track to follow. If there isn't a dedicated track for you, you're probably looking at the wrong conference or you need to pick the needed parts.
Make a schedule for yourself.
If you are done setting the basics, you can build your own schedule. Look at pause times and locations. Not only the biggest conferences tend to move into more than one venue. So you have to keep an eye on the time it takes you to get from one location to the other. Also plan to include additional time for discussions afterward. You always find some controversial sessions which content will lead to further discussions with either the audience or the speaker. If you are going for them, plan the needed time. And don't forget to keep an eye on the opening hours of the exhibition hall or some extra time needed for demos. And most important: Plan your spare time. Find the parts of the conference you probably could skip, if you are in need for some sightseeing. Especially those conferences happening in far away places have the quirk, that you will spend too much attention on planing sightseeing on-site. Better put this into the overall planing and preparation phase. If not possible, try to plan the spare time for it and ask the concierge or some locals for their help. Having this planned helps you staying focused on the content parts of your conference.
Another possible addition to your overall schedule could be some time for socializing. As you might guess, this is not really plan-able. You simply don't know whom to meet and which friends to find over there. Instead try to be open and outgoing generally. You will not make any new connections if your are walking from one session to the other having the chin on your chest. And don't forget to say "hi". Everybody is wearing name-tags. Use them. Everyone is there to meet people and find new ideas. People at conferences want to meet whether you are a PM or an energized newbie.
Be inspired and open to new ideas!
Conference are popular because it’s pretty hard these days to stay up to date in any field by sitting at your desk reading magazines. So the conferences are the place to find out first and foremost about new stuff. Don't go there if you are not willing to change your mind or find new ideas. Learn about approaches taken by others. Hear about best practices from practitioners.
Most conference panel sessions and even some keynote sessions encourage participation. For panels this could mean, it's a good idea to approach the speakers or moderators beforehand and don't wait in line afters. Tell them about your interests and instead of leaving boring or slow moving discussions: take control! If someone talks off-topic: tell them! If you’re bored, others are too! Try not to ask questions that only matter to you. And try not to ask vague questions for which there is no answer that matters. If possible, try to make panelists take a stand. Controversy is exciting!
Work hard. Play hard.
If you have a packed schedule and you are soaking in all the news all day, you are definitely working hard. So you have enough reasons for playing (a bit). Beyond the serious stuff in the conference hall, there are usually dozens of parties and events going on. Some during the day, but most of them in the evenings or even nights. Companies often have contests and concerts at clubs, restaurants or hotels nearby. It’s a great way to meet people and socialize.
Bring something home.
If you are away for a conference or two a year you are probably leaving someone behind. Mostly this will be the rest of your family. Wife? One or more kids? You miss them, right? Yeah, you do. But they also do. Instead of thinking about them every minute and sending tons of text messages home, find some swag to bring home. There will be something for your to grep at the exhibition hall, at a gift shop, at the airport.
Make the value of the conference transparent to your employer
Reading a magazine regularly is far cheaper than attending a conference. Taking every little bit into account (travel, hotel, pass) you quickly end up with quite a sum. So, if you don't pay yourself make sure to bring back some value for your employer. Being a speaker this could be easy. Tell him how many people attended your session, where you put the slides, where you were walking your company t-shirt around. If you are attending and contributing like a regular attendee, think about having some public talks in your company about what you learned. Prepare some lessons learned for your fellow co-workers or even write an article for your companies own magazine. As said before, conferences are not only fun and play but hard work. Make sure, your employer get to know what's the value in there for him.