Let's try not to screw it up, huh?
If your date's grandfather would have been wearing your clothes, you may have some chance at them being fond of the retro look and thinking that you're just being stylish, especially with the vampire culture crossing over with goths from time to time.
You're trying to look normal, so how about going to a normal store? Find something comfortable, something that they wont think looks too awkward and just try to be yourself.
DON'T: Go for the spray tans.
Since you can't get out for a day in the sun like other people, some people would consider alternatives to get that healthy glow. Makeup, tanning booths and spray-tans are all relatively common. Unfortunately, for someone like you, the amount of makeup required would be absurd and tanning booths come with some health concerns you should be wary of.
Pale skin is in! Turn on the TV, find some of your kind and realize that they're all flaunting their natural alabaster tone! And it really works for just about everyone!
DON'T: blindly follow the fads
One of the things that's really gotten popular among people like you is to follow the person who started the recent swell of popularity for your people. I mean, how can you not? He's made your lifestyle trendy for people who would have condemned you before.
What you do with your hair, in the end, is important only because of what it does or doesn't do for the general area around your head. Or, to make it easier to understand, you need to make sure it fits the shape of your head.
Experiment with the hair until you've achieved a look that works for you. You may even want to try some colors, though beware, some brighter colors will look a bit strange with your skin tone, so take care not to go too extreme with it.
This really doesn't require too much explanation. Just say no.
There are a lot of methods to making this work. Many of the dental products out there for the average person will probably do you some good, whitening will make even the most intimidating smile look lovely.
Consider dental bonding!
And if you still don't quite feel comfortable going out in public, try settling in with a good book instead. How about mine? :)