OK, not so much trying to hard, but trying to desperately then? Looking back on my youth, I can see why I wasn't so attractive then, and it had nothing to do with my physical attributes.
I would say that being persistent or showing steady intent would be good but, as you said, being desperate would be unattractive. Maybe there's some masculine equivalent to the expression "Don't play hard to get. Be hard to get." which is one of the femininity mantras I'm trying to understand (sigh.)
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver