Hi, tastiger. As I was the one who made the comment about shadows being 'washed out' it's only fair I try and give you some tips :-)

I spend absolutely ages on lighting. I tweak, remove lights, add lights, change the colours and brighness, turnshadows on and off, etc, etc

Lighting is a very large part of how your final render looks. Changing the lighting can seriously alter how your textures look too. When you have assembled your scene try to think a bit like a photographer. If a shadow is too dark and hiding detail you want to keep then add a light, turn off shadows for that light and gently bring up the brightness until you can see what you want.

A mistake I used to make was trying to make it 'real'. In other words only use the lights that would be there in reality, just the sun for an outdoor scene for example. Now, I try to use lighting to make the mood of my picture work for my intention. I also turn off ambient light unless I really need it.

Learn to look at your work and see what is not working. This was the biggest thing I learnt from Art College. How to see what was not right with my work and keep working to realise the vision in my head.

But, as it411 said, you have to be happy with it. It's what you want to do as an artist that counts. If you like what you have done and someone comments feel free not to change anything. If you agree with the comments then you might want to try again.

Oh and one last thing, every picture is different. What worked for one doesn't always work for another :-)

Hope this helps and keep posting.

Regards
Tony