Here is a sample with construction lines. My dovetails aren't pretty, but you should get the point. The dotted lines are construction lines. They are good for laying out dimensions and so forth and are easy to erase. To make a construction point, once you have established the first point with the tape measure, tap the control key and you should see a plus symbol by it. Either stretch it to where you want, or type the value you want in and click or press enter. Once you have two construction points, you can use the tape rule to do a construction line. Again, establish the starting location, tap the control key, and go to the second construction point. This way, you have reference lines to draw both sides to match.
Once you want to get rid of them as your drawing starts to get cluttered, I assigned a hot key (as recommended from who I learned from) to get rid of them all at once. Go to windows, preferences, short cuts and find construction geometry, erase all. I assigned E (as was recommended), and it is nice.
Construction lines are excellent for this type of thing, and for laying out dimensions before you start drawing the actual components.
Another trick you will want to use is mirroring. Say you draw a side of a dresser with dadoes, mortises, etc. You can make a perfect mirror of it with the scale tool. just change the value to -1.
It can be aggravating, but once you get the hang of it, it really is a neat and easy to use tool.
Good luck, and hope I helped.
