I think staying classy can be taken too far if you're not careful. Sometimes doing slightly embarrassing or vulnerable things helps you build connections with trustworthy people. Sometimes, it just can't be helped. I'd say worry about being kind and respectful, but don't worry too much about things like ... crying or puking. They're not particularly classy, but not a big deal either.
Most social groups I'm part of would consider puking to be a serious failure of self control. Most of the male-dominated groups I've been in would view crying the same way. I think that one is really "know your audience".
I'm not as smart as I like to think I am. Knowing that, I've gotten into a habit of trying to work out as many general principles as I can ahead of time, so that when I actually need to think of something, I've already done as much of the work as I can.
What are your most useful cached thoughts?
A few of the rules-of-thumb I've already pre-cached include:
That should be a reasonable but not overwhelming sample of the sorts of ideas I mean, and am hoping to evoke more of with this post.