I started working on interiors in Revit also. I ran into several little things as I worked through my first attempts. Some key points

1. Don't just render a high quality image right away. Takes time and you don't have any idea of your lighting. I start with a quick draft to check lighting.
2. If doing a render with sun and artificial light, you may need to tweak the light out put of interior lights or adjust render exposure. I also found changing the sun angle from 35 deg to 70 deg.
3. Play with your materials, you can adjust settings for all materials, you are not stuck with out of the box materials.

First Try at Rending in Revit

Here are the results of my first tries at Rendering in Revit. I have been busy work in a different areas in Revit, but I have not spent much time on rendering. I found the quality of the images to be pretty good for my first major attempt.
I have noticed a few items. First the Exterior Rendering is easy. Make sure you add some ground below it, looks funny floating in mid air. I did this by creating a separate project for the site. I created a Topo Surface and divided it to create the parking area and grass. I also created a floor for the concrete walks and added some plantings.

This image is a dark, but shows the concept. I added exterior lighting and created a night rendering. I had to adjust my materials on the CAD EXPO sign at the top of the building. I adjusted the materials and adjusted an area for the material called self-Illumination. I would also adjust the exposure settings the next time I render the view. That would allow me to adjust the exposure.

Up Date: I have adjusted the exposure setting and rendered it again.

Revit Building Construction Types

I have had several people ask about this. How does Revit MEP under stand construction of the building and R values. Let's first say "there is no connection between the MEP Space and the Architectural Objects." We are required to specify this information.

What are you saying?

Revit model requires us to tell it what the construction type of the; floors, roofs, walls and glass. This data is added in the Project Information under Energy Data. You will find Building Construction click the "edit" button, that will open a dialog box that will list different construction objects. You will then choose from the drop down lists what primary Construction Type is for the objects. This will set the defualt for all the MEP spaces. You can over ride the construction types per space as needed.

I can't find the Construction Type I need.

Then you will need to add it to Revit. It is very simple to modify the constructions list, as well as add new wall types. Under C:\Program Files\Revit MEP 2010\Program\Constructions.xml you can open the constructions file with wordpad, and using the same format as the pre-defined ones add your specific wall, roof and window types. Make sure to keep the syntax the same, as well as keep the ID unique. Here is the xml format:Important things to note are, make sure you place your new construction under teh correct type, for example c for ceiling, w for wall etc. As I mentioned before also make sure to name the id unique. After you make the changes simply restart Revit and tehy should appear in the construction types.

I hope this will give you some additional in site and help.