1) Apparently it's rude not to friend someone back if they friend you.
Okay here's the thing. I'll friend you if they say something interesting or post good fic. Since I don't really do either of those things I'm always amazed to see that I've been friended back. Just so you know I won't hold it against anyone if they don't friend me back. (That's not to say I'm not delighted to have you guy's in my Flist :).
2) Comment on fic.
I try to do that pretty consistently, but if I'm finishing up at 2 in the morning, you're shit out of luck. But I love you for writing anyway.
3) Read your Friends list.
Confession; I rarely do this. I check in with my regular coms and I haunt my myriad of delicious networks. That gets me a bunch of fic recs a day and from there I'll spread out and work my way back through your journal. Or I'll do the same when I reread your fic from my Delicious account (which I do more often then you might think). So if I'm leaving comments on all the charming things you've written weeks ago... it's cuz I'm using the internetzz wrong. (okay fine, it's because I've managed to turn my Flist in to community spam box and like my previous email inboxes, I'll do anything to avoid cleaning it up)
4) SGA kicks MERLIN's BUTT!
There I've said it.