Hey Slim, keep up the fitness training, because a reticent, slightly unsure-of-himself man in a fit, sexy body is, shall we say, a godly gift to womankind. You might not have to do the pursuing, after all. Wouldn't that be nice?
As for that insanely cute nephew -- USE HIM. There is no man alive who does not look better with an adorable toddler in tow. Give his parents a break, take him out and about, to parks and art museums and on trains, and you'll soon be in conversation with all kinds of people, especially women.
Sample conversation:
"OMG, your son is so damn cute!"
"Thanks. Actually, he's my nephew, but I like to practise with him for when I have my own kids."
"Oh, that is so lovely. So, are you trying for a child with your partner?"
"No, I'm single, but I hope to have a family one day."
Woman thinks: He is gorgeous -- and the baby nephew's not bad, either!