It's not always easy to measure precise distances on the fly with a tape measure. If you want a quick method, Instructables user bfk suggests punching out holes with a hole punch so you can quickly judge distance and make marks.
The idea here is that with the holes punched out in the tape measure you can instantly make a level, precise mark on a wall if you're planning on drilling or nailing something into it. Likewise, it makes it easier to quickly judge short distances.
At a glance, it looks like it would ruin the structural integrity of the tape measure, but bfk says it holds strong. Head over to Instructables for the full guide.
East to Make Precision Tape Measure [Instructables]