You should post a screenshot of your non-detailled map, so we can better understand your problem.
Reading ur post, I think u might even just have ambient light and neither light entities nor sun light, which would make your map look rather flat as well.
About the settings in mbuilder, you could read
this article about advanced compiling, which will explain, that for example fulldetail is a bad idea in general. I personally do
"-blocksize 0" for BSP
nothing for VIS
"-final" for LIGHT
Then, you will find some other nice tutorials here at .map, that u should take a look at.
About the usage of detailled brushes, I strongly recommend
this article over at the Rjukan Project. And you surely will find other helpful tutorials there, too.
cu wacko