Dating: Best way to be comfortable.?

So I'm new to dating and stuff. I'm not looking for a serious relationship and just casual dating or just meeting up, but I am sure this applies as well. Lately I've been making errors (unintentional) and am learning about these "dating rules" and someone I know called out on it. Learned a hard lesson that way. Anyway, I know they say have to be yourself and just be natural, however I am starting to realize people have different expectations and observe and perceive you differently. If I do or say something that really just simple, some of the guys I met up would take offense to it. Is there anyway to go about this. I mean tell every person I meet that I'm not looking for anything serious now and just want to see how this dating thing works, however if there is a "connect" between us I'm willing to take the next step. I tell ppl off when they cross the line and ask for sex and stuff the first night. But I just feel weird getting into this now and want to know how to make myself comfortable and not worry about giving people a wrong perception. That's all.

Also even if I don't want a relationship, is it smart to keep contacting those guys to keep as friends even we both know we won't get anything farther than just hanging out or is it necessary to drop them for good? I've been talking to few, but just as a buddy not as a potential girlfriend.