I have a client, that wants me to design a site for his band. The problem is, that I can't really figure out what colors to use?
I've done sites with very variated colors, but this one is hard.

What do you refer to a bandsite (goth-style)?
Red. Bloody red, is the correct answer.
A pitch black site, with #e91a1a as main-color.

How do you do? I've tried a numerous of times, making the site look good, but it ends with I'm not satisfied.
I need some guidelines.

Have you done something similar, please post a link.

/Andy

I have a client, that wants me to design a site for his band. The problem is, that I can't really figure out what colors to use?

Translation: I have a client, that wants me to design a site for his band, but I'm not a designer... OK, so that's a bit harsh. It might be that you need some inspiration. Go to a show, download their music or similar music and listen to it throughout the day (even if you hate it, you listen to understand it, not enjoy it). Take notes (mentally or on paper) about what images you see and imagine. Take photos at their shows, or Google some rock show photos.

I hardly ever start with making a decision about color, it usually comes as a result of creating the design. Colors will pop out of photos, past graphic work, etc., and they'll feel right.

It's not about you it's about [you satisfying the] client with the final product.

More specifically, it's about you satisfying the site's audience. It's about you creating something that generates more interest and buzz around the band, getting more people to shows, getting the band more gigs, and/or selling more merch.

Also, sounds like you're fairly new to design. Let this be a learning experience for you. Have fun with it, try new things, new techniques, new styles, and I'm sure you'll end up with something good. And please share in the process. I have no problem reviewing someone else's work if will help them (I don't care what the forum's rules say).

I'm in a similar situation right now—at a point where I seem to have a lot of enthusiasm for a project but not a lot of direction. We just presented the wireframes today, which the client was mostly happy with, but so far my visual design attempts have been uninspired (doesn't help that the logo is atrocious).