The way to get people to know you, attach your name to your face, and realize you are knowledgeable is, maybe suprisingly, to ask questions at meetings, as often as possible. You do not understand something about a plot your colleague is showing during his talk ? Ask about it. The x-axis labels are missing ? Ask what the heck are the units, even if Groucho's child of five could understand it. You arrive before the last slide and the speaker is saying she measured x with two inverse femtobarns ? Sit down, wait ten seconds for the dust to settle (you do not want them to see you have just arrived), and ask her whether she plans to add more data to improve the measurement. You doze off during the talk and wake up at the Summary slide ? Ask to see slide 7 again (there is always a slide seven, so this is a safe call), and then stare at it pensively for five seconds, finally saying "Ok, I see, thank you".