If your nails are too long, what girl is going to want them inside them? Manicures are incredibly relaxing and cheap (especially if you're not getting polish as the ladies do, but if you're into that I don't judge).
If they're dirty, they're definitely not going to let you slip a finger in, no matter how good the make-out sesh is. Throw down 15 dollars every few weeks to get your nails done and a pretty killer forearm massage.
If you're trying to get laid, you're going to need to do something with your hair-down-there.
You don't have to go total bald-eagle (unless your hookup has made it clear that that's the hairstyle she prefers for your peen), but you certainly should trim.
Even if it's just a body shower, please fucking shower.
Rinse off your day (and all the sweat that came with it) before you plan on encountering any ladies. Take a whore's bath with some wipes or a washcloth.
I highly recommend these for after an intense upper-body day at the gym.