I don't do online dating. If I did, though, I'd make sure the person on the other side is not some psychopath manipulator rapist. Ya know... too many bad experiences to count.
I'd look at his profile and, if I liked what I read, I'd talk to him to make sure he's not lying. I'd study his intentions carefully. One does not like to be fooled into thinking someone likes you, when they only want to take advantage of you.
If the person was himself from the very beginning, even better. Saves a lot of time from being wasted on psychoanalysis.