A thing I'd like to add when dealing with the comics community is realizing that we don't all get along & get geek rage over certain things & you have to respect that. If you haven't read a superhero comic in ten years, you don't have the right to make fun of someone who loves Green Lantern. Some people hate funny comics, some people hate sad comics, some people hate action comics, & it's a good idea to have one or two things you can talk to people about regardless of their favorite genre (& yours) as something you legitimately like. I'll talk to any fan of super heroes about the first Human Torch stories for hours (because it is awesome) & I'll talk to sad story people about Will Eisner (who is surprisingly little read) & manga people about my love & frustration for that genre (I miss the 1980s when mangas read left to right & everyone was left handed in the drawings (which I never noticed until somebody told me a few years ago)). People who like funny jokes & are routinely swearing in conversation, I point them to Super Haters.....
I also personally try to always offer to help someone (be it offering to split shipping costs when sending out some books for promo or doing a proofread before a print run) & plant a seed for a possible collaboration in the future.
Also, if you don't have anything to say positive - just start talking about what kind of pens they like.