I got tired of waiting and turned to Rhino3D and god it's so much better than Sketchup. But still when SU7 comes out I'll get it, because it works way faster for simple stuff.

Check out this.
http://www.pushpullbar.com/forums/showthread.php?t=6184

You say you're from holland, so you wouldn't mind reading it in Dutch I guess, there's a Dutch and English version of my tutorial available at my forum, you need to register to read the Dutch version, not the English. enjoy.

It explains most of the things to achieve a good result. The basic workflow. Some things might be changed since Maxwell 1.7 but not that much.