boring stuff that won't go anywhere in getting to know the person - like weather etc - also don't have any convos that will mean you are talking about someone you dislike eg a boss or how you don't like that one guy cause of x,y, z. How a person treats others says a lot about them so if you start talking about a certain person in a way that isn't exactly complimentary of them - it doesn't look good. Also I hate guys (and girls too) that gossip about people. Don't start up a convo with a rumour or gossip - not a good look bro.
Andddd be positive - if you are optimistic and positive; people like you more (apparently) - no point starting with negative comments about your day etc or with the heavy topics off the bat (like exs, mental health-avoid avoid until you know each other better) - pick light hearted topics that you can laugh about and look like a guy that doesn't take himself too seriously- and that won't scare the person away! good luck!