I think wearing makeup, girls clothes (obvs), generally acting camp and girly makes you a "girly boy". Stuff like moisturising is metrosexual and simply looking after yourself.

And also boys who care too much about what they look like

I still think some metrosexual things are "girly". But that's obvious, otherwise why would we give it a label in itself. If it was something not to batter an eyelid at - we wouldn't have saw it as anything different.

I dont moisturise but I know loads of my friends that do, I wouldnt call it girly, i just think they care way too much. Like the same when they get their eyebrows done or waxing... i just tell my friends they are a bit weird but not girly.