I didn't do OD for long, but my rule was - only people who had clearly read my (short!) profile got a reply.
I ignored the "hi" and "fancy a chat?" ones. Also "how's your day?"
Also the lame jokes. I actually had "if looking sexy were illegal, you'd be guilty as charged"
Winks and favourites - ignored.
A one liner was fine, I don't expect people to invest a lot of time when they know they may get no response.
I personally think that "trying to be funny" just falls flat most of the time. Friendly and interested was fine.
I used to feel irritated by the "tell me one word that describes you" or "take my quiz" type stuff. It's not a test, just talk to me.
So - short, friendly, no cheesy jokes, no flirtation. To be honest, I didn't even like the "you're stunning" type comments - I mistrust them! I know we all message people based on our physical attraction, but comments like that are too blatant for me!
Refer to my profile, but add something, don't just say you like it too. And throw in a question, so it's easy for me to respond. e.g.
"Hey I liked your profile! I love camping too. Last Easter I went to Wales - rained every day but I still love it. What kind of spot do you like best?"