A girl could be a great singer and still be a nerd. All of us are nerds in some way. Unless you are just a dork! There are certain things which you need to know before you make an attempt at dating a nerdy girl.
Doesn't understand your gestures or indirect approaches
Forget those normal ways of approaches, by showing signs like smiling, asking for a pen, or something of that sort. She is so engrossed in her thoughts, that she might never notice your indirect gestures. The only language she understands is a direct one.
Very bad social sense
Yes. If you are too careful to spoil your image, this is an alarm!! Don't approach a nerdy girl at all, 'cause you've no idea when she will laugh out loud in a silent space over a joke she heard two days back. Or when she'll be crying puddles of tears in the memory of her favorite late fiction character.
Introduces you to new dimensions of her world
Trust me, you will enjoy a nerdy girl's company. You might get to know about many different things and facts about the world you didn't even know would exist. And that glow in her eyes while talking about them to you will make you fall for her all again.