SketchUp is great for creating detailed models quickly but the output formats that come built into it are a little cartoon-y. In most situations they are great for getting an idea across but when you want to present your model in a slightly more photo-realistic format you are going to have to rely on a third-party rendering application or plugin.
To create renders of your SU models there are many options available. There are those that use an export of your model from SU and then render the image after further work on your part to describe the lighting and materials. There are those that work inside of SU itself allowing you to add lighting and material information and all other rendering settings and parameters within SU itself. I am not an expert but the former seem to be cheaper but have a much steeper learning curve than the later which, unfortunately, tend to be much more expensive. As a rendering newbie I wanted the simplicity of the rendering application hosted within SU itself but I wanted it at an affordable cost. Just at the right time for me the Twilight Renderer application was released: I couldn't pass up the simplicity of having the renderer withing SU for the affordable price of less than $60 (until September 24th).
I've played with it a couple of times without even reading much of the documentation and I am getting some pretty nice images. I'm not really in control of everything yet but it looks like a fun utility and I don't have anything to compare it to but it seems relatively simple to use. I look forward to learning more about rendering but, until then, here's one of my first renders of a couple of models I worked on over the weekend - you have to be a big old Sci-Fi geek to know these guys: