The key is to pick your sessions carefully. You can't just go to whatever you feel like, choosing sessions at random, unless you want to have a fruitless conference. Instead, you should carefully select the seminars you want to attend based on how much you will get out of them.
Sometimes, this might involve doing a bit of research. For example, look up the people taking each session. They might just be people who know a bit about the topic they're talking about, or they might be published authors and experts in the field. Often this information will be included in the agenda.
Obviously you will want to be going to the sessions taken by the most experienced, authoritative speakers. However, that is not the only concern you should have. For example, how much is each session relevant to your job?
You might find there is a really interesting session on human resources, taken by an industry expert, that you really want to go to. However, if you are an accountant then it might not be relevant to your role. It is usually better to opt for sessions that will develop your career skills, even if it means missing out on ones that are potentially more interesting.
Think about your level of knowledge in a field as well. You never want to go to a seminar that you could teach yourself - if you won't learn anything new, it will have been a waste of your time. Make sure you choose subjects in which you are a relative beginner so you have plenty to learn.
This might seem counter-intuitive, as it is playing to your weaknesses rather than your strengths. However, following these tips will ensure you have the most fulfilling experience possible the next time you attend a conference.