If you’re looking for a good woodworking plan, there are a few things that need to be considered.
1. Is there a cut sheet and or material list? A cut sheet is the parts of the piece individually noted and dimensioned so that they can be properly fabricated. A material list is a shopping list so you know how much wood to by and what type.
2. Is there an overall picture of the finished product? In order to get a good idea of what the completed project will look like and how it is assembled there should be at least three views of the project. These would be the top, side, and end views. And are these views projected (lined up) so that they can be scaled and visualized during the construction?
3. Is there a fastener list? This isn’t a top priority, but it is very helpful to know what screws, bolts, glue types, brads, or nail types go into the project.
4. Is it alterable? In other words can you easily modify it with the information given so that the piece will fit your needs if necessary.
5. Is the drafters name on it so that if you want them modified, he or she can be reached? This may be something you hadn’t thought about but important none the less.
6. Is it printed on a readable size of paper and scale? If not you may not be able to make out the dimensions and notes. Is it supplied in an easy format to print such as a PDF?
Tim Davis has created a very complete course on learning to draw mechanical drawings in a CAD program at http://mechanicaldrawing.us/