When you're spying on people (or spying on girls ;-D), it's very easy to loose track of what happened when...
If you're really serious about spying, you need to keep a journal when you're tailing a subject. That way, you get great insight in the daily routine of your subject.
But it will also show you when something out of the ordinairy is happening. If the person you're tailing is always going one route, and suddenly walking another route, pay close attention! It may very well be that he or she is going to meet with a contact!
So, it's important to write it all down in your own Tail Journal when spying on people.
Below you can download a PDF file you can use to make your own Tail Journal. It's formatted in such a way that you can print it (double-sided) and fold it into a small booklet in which you keep track of your shadowing practices.
You can now continue to download the file by right-clicking on the link below and selecting "Save target as..." or "Save file as...". Then select a destination where you can easily find it again (like your computer's desktop) and click "Save".
Instructions: print out the file (double-sided! Most modern printers can do this automatically, but you most likely must select this setting in the printer settings). Fold the pages (al 4 of them) once along the long side. Staple the booklet, and you're all set to shadow your subject!