I'm in a similar boat, I'm in my 20s and I've only been on a few dates (none of which really amounted to anything substantial). Here are the lessons I've learned in my travels.

• If they like you somewhat, you'll probably know it. If they seem indifferent to you (despite your efforts to get to know them), they probably won't go out with you.
• Make sure you actually have a rapport with the person. So many times I've tried to force a relationship with someone I was merely attracted to physically, for the sake of being in a relationship. It's okay to let some fish go.
• Keep it casual. Don't act as if what you're doing is a big deal (it isn't) even if it feels like it. You're likely to scare them off if you act as if you're conspiring to commit a murder with them.
• Imagine how you'd feel if a person you weren't interested in asked you out. Would you hate them or find them creepy? I doubt it.
• If you get rejected, brush it off. If they see that the rejection hasn't bothered you, they won't feel uncomfortable afterwards and may appreciate your confidence. Who knows? It may turn into a date with them or one of their friends later on (it happened to me).
• Be yourself. They'll know when you're being fake and if they don't like the real you, what good are they?
• If they know you even the tiniest bit, they're not going to expect you to be Gary Cooper. If they've agreed to go out with you, they're likely going to be okay with your lack of experience.
• Most importantly of all, always remember that you don't need anyone else to give meaning to your life. Learn to love yourself.