Weekend after weekend, students shoot themselves in the feet because their targets cannot hear the material. You can be the best pickup artist in the world, but if she can't hear you, your chances drop dramatically.
Yes, body language can play a huge part in getting you the woman of your dreams. That said, I guarantee that if you are in a loud Crobar in Miami or New York City or Light in Las Vegas, you will not stand a chance against a better looking, better built guy in more expensive clothes when the volume is cranked to 11. If you were that good looking, you probably wouldn't be here.
Of course we point this out, and of course students hear my Marine NCO, theater-trained voice, and they think, "How can I possibly be that loud?"
Your vocal projection rests on certain muscles, and if you have a weak voice, you must work those muscles, just like you would work your arms or chest in the gym. Good vocal projection comes from your diaphragmatic muscles. A lot of people have no idea where these are.
To find out what it feels like, put your hand on your belly and expel all the air in your lungs. When your body demands the air, you will feel your belly expand. These are the correct muscles. Get a feel for breathing from there.
Now that you have some feeling for it, try producing words on the breath. Your lungs expelling air will produce a considerably more powerful sound than what your vocal cords alone could achieve. It also has the cool side effect of not messing up your throat when you spend night after night in a venue. This is why Broadway performers and opera singers are able to do what they do.
Practice time: Get a partner. Stand a normal distance from him, and say some mantra. Long or short, silly or normal, whatever. But it should be the same. (e.g. "Unique New York," "Sally Sells Sea Shells on the Sea Shore," "He Thrusts His Fists Against the Posts and Still Insists He Sees the Ghosts," or, of course, the hook of your favorite opener.) Visualize the sound hitting your partner.
Now pick a spot a good distance behind him and visualize it hitting there while you speak. Try to sound natural, and make sure you are speaking from your diaphragm. Drop your shoulders, keep your chin level, and don't be afraid to open your mouth a little wider. If your partner can't hear you clearly, have him tell you to repeat both parts.
Take a step back. Repeat.
Take a step back. Repeat.
Keep it up. Eventually you will put some serious distance between you and your partner.
Focus on sounding natural and breathing correctly. Eventually you will reach a point where, if you're not breathing correctly, you simply will not be able to project to a suitable level.
Do this regularly for six weeks, and you will find considerable improvement in your vocal projection abilities. Also, while you're improving, check yourself periodically and see if you're breathing from your diaphragmatic muscles. (Hint: if your shoulders go up and down, you're breathing from your chest and you need to realign.)
These are things I do, and I offer the other instructors and their experiences as proof. When Soul finishes a live workshop, his throat is tore up from the floor up. I'm ready to shout at small children.
Having the loudest, most noticeable voice in the room is a very important trait for a dominant man, and if you want to improve your success with women, it's very important that you make material gains on your vocal abilities. I can guarantee that most people reading this need to be louder when they approach a group. Doing what I recommend will help you considerably, but as with any area of your life, nothing can replace personalized instruction from someone who knows better than you. If you're serious about improving your voice, go see a voice coach.