Over the years, I have evolved from providing 2D Construction Documents for obtaining Building Permits to introducing varies formats for presentation and documentation.
Here is an example of a partial set of construction documents for new construction:
Besides Construction Documents, I also provide drawings for interior design uses such as furniture plans, kitchen design plans, bathroom design plans, tile layouts, etc.

Designed by Genoveve Serge Interior Design

Designed by Genoveve Serge Interior Design
I also do colored plans and material boards:

Designed by Genoveve Serge Interior Design
I started using Google SketchUp to provide basic 3D presentation. This is an effective way to help clients visualize the not-yet-existing spaces. The format can be either still images or walk-through videos.

Designed by Geometrix Interiors
(Designed by ARKIECO)
(Designed by Geometrix Interiors)
(Designed by Michelle Chiang)
When I was in college, I learned how to draft and sketch by hand. I enjoyed it.
In the real world, I sketched just to communicate ideas. It was nothing formal. Last week, at the last minute, I had to do some sketches for Wendy Weiner Interior Design for a presentation. This is what we ended up with:

Designed by Wendy Weiner Interior Design
I am so out of practice! I need to get back to hand sketching.
Not everyone is cut out to be an interior designer although I had hoped to become one. I am glad to have found my niche working in this industry.