Scientific conferences are a great place to get your name out there, discuss research with colleagues, and meet other researchers with whom you might one day collaborate. It can be difficult to get noticed as a graduate student or post-doctoral researcher, especially if it’s your first time at a certain conference, if your poster time conflicts with more interesting events, or if you find yourself way at the back of a 1,000 poster hall. You need to be ready to introduce yourself and get your point across, and to do it in a memorable and concise way. There may be hundreds or even thousands of people in attendance, so you need to make a fast impression.

Though a bit outdated these days, I find business cards really handy. Not only can you quickly hand out all your information, but you can write notes on the back about what you discussed with someone so you can follow up with them later. It’s easy to leave a bag of them at your poster for people to take, too.
Not only is your poster or presentation’s content important, its visual appeal will help draw in people who are “browsing”. Make sure your font is large enough to read from 5-8 ft away, and that you have some color, but not enough to make text illegible. Bolding or bulleting take-home messages can also be really helpful. Make sure you can describe your poster in a variety of ways: in under 60 seconds to the person with a mild passing interest, and in-depth with the person that is curious about your methods or your other projects.
The most important thing to prepare, though, is yourself. You are representing yourself, your institution, and your science. Cleanliness, organization, and confidence make a huge difference when meeting new people, and will make you more approachable. Make eye contact, try to avoid filler words, and smile! I have watched posters get overwhelmingly passed by because the presenter was on their phone, or looked bored or annoyed. Making eye contact and saying hello to someone as they walk by is often enough to get them to slow down and ask you about your work.

When asking questions at other presentations, be sure to be polite; being demanding or rude is guaranteed to be met with disapproval from the rest of the audience. And go ahead and introduce yourself to other researchers, just be sure to keep it brief and don’t interrupt another meeting.
One more thing to consider at a conference is your behavior outside of your presentation. You are at a gathering of intellectuals who may one day be your boss, your colleague, your grant reviewer, or otherwise influential in your career. They may remember that they saw you talking loudly to a friend during a presentation, or that you got too drunk at the opening session. Conferences are often used as an excuse to take a concurrent vacation, especially for those in academia who generally can’t take a week off during the semester. But you should remember why you are there and act professionally, especially as a graduate student or post-doc, because you never know who’ll remember you in the future.