Make sure you let the crew know you're there, especially if you're trying to get on a full -100. The gate agents aren't always forthcoming with the information when there are more passengers trying to get on, and sometimes don't even want to tell us when we specifically ask. If there are a couple of kids and few enough bags, it's rare but not unheard of for us to get 37 and a jumpseater in a -100... I did it twice this month already.