Just to add on:
Avoid meeting in nightspots like pub/disco on your first meeting to club.
This provides an opportunity for the guy to spike your drink or have his friends to spike it.
Bring along another female friend..
It helps, especially when u wanna get away in situations, just give excuse u going ladies with yr friend, come up with some lame excuse, tell the guy nicely u got some reasons to leave.
If u cannot click even as friend, be nice to let the other party know you are offended so that he will not repeat the same stupid mistake again, so that he can have better chance of knowing others thru this forums..
Just my 2 cents