Whispering means you are either telling the other person something risqué that you don't want others to hear, or that you're looking for an excuse to be closer to the other person in order to tell him information he -- and only he -- is privy to. Make the whispering extra sexy by building up the moment. Ask if you can whisper something in his ear. When he agrees, simply lean over and tell him something like, "I love your shirt," or "I just wanted to let you know I'm having a great time tonight."
If you're having a good time with your date, show him that you enjoy and appreciate his company by giving little flirtatious touches now and then. This doesn't have to mean full body contact, like sitting on his lap, but you can touch his arm when he's telling a story or a joke. If he has a little cream on his cheek, feel free to grab your napkin and softly swipe it away. A guy knows you are genuinely interested when you take the time to brush his hair out of his face.
As he tells the story of his childhood, tilt your head to the side and nod understandingly. If she's telling a touching story about her parents, grab her hand. This demonstrates that you are capable of emotion and are willing to show this side to her.
Skip the twirling your hair around your finger or the batting of the eyelashes and get right to the point. There is absolutely nothing wrong with telling a guy that you like him. Tell him what you find attractive about him or tell her how you are mesmerized by his beautiful smile. This not only demonstrates confidence within yourself, it also shows that you feel comfortable enough to share this information with him.