Although this video was created using AutoCAD 2008, the same commands and techniques apply to newer versions. View the tutorial that relates to this video.
The video below shows how to draw the Computer Room project. It's a simple floor plan, but will give you an idea of how to approach similar projects. I try to start from the outside with the largest areas and work down to the details. When you finish this. Measure and then draw the room you are in now.
You can view the first part of the project with this video. It will show you how to drawing the floor plan.