Usually its the basic, general things like, well mannered, sweet / caring etc. As far as more specific things like personality wise, every guy likes a nice personality, but what he likes for himself is what varies from guy to guy. Like there are guys who prefer quieter girls, and other guys whom like louder or more extroverted types. Some guys prefer a housewife type of girl, others have a different view. Really it depends on that particular dude.
I say, just be who you are; you can't impress every single man, but the one you do will definitely show his interest if the feelings and attractions are mutual.
Well personality wise I like when girls are loyal,have their own opinions with stubbornness and spunkyness added to the mix. A pushover is not a very fun partner to have, in my opinion. As far as her interests goes, I don't really care, I mean I'd like to have a few of the same interests to have common ground, but not too similar, since our differences makes things more interesting. Also I'd like her not to push things on me, like her religion, political view etc. I make my own mind up about that and as I won't interfere in her views, she shouldn't try to do so with mine.
Physically though, I'm less demanding, since nothing is really a big thing for me. As long as I find her attractive, which doesn't rule out much. Red hair is a plus, but it's not a major thing.