One of the first things that they drummed into us at design school was that we are communicators. One of the first thing that was drummed into me when I started working for a web design firm was usability. In a way, these are the same concept.
Don’t let the design get in the way of the message.
One of the most biggest professional learning curves for me was understanding when to trim it back, when to simplify and when to accept that, yes, practicality will sometimes get in the way of my genius (har har). So, a few years on, I can still look back and understand why some websites are the way they are despite the usability flaws.
Which, belatedly, brings me to my point: there needs to be contrast in your design. I went on a joining spree of fanlistings lately and I’ve had a difficult time with some of them. Believe me, I don’t want to be the one to step into your creative vision waving the practicality flag, but if I can’t read your body text because it’s too close to the colour of the background, I’m going to leave. This is the same for form styling, I need to see what I’m typing! When you’re designing your site, you need to remember that lots of people with lots of different monitors are going to be viewing it, so even if it looks fine to you, it may be completely unreadable to others. So punching up the contrast ratio of your text/background is probably a good thing 
1
I’m not going to go into the theory of Contrast as a Design Principle because, frankly I’ve written too many essays on such things. And, DesignMeltdown already has a great article.
1 To clarify, I’m talking about the content text, not headers etc.