Marco, what I do is to have a Cyrodiil map in a good png quality and just go marking Xs on the places I had visited.
The best map I'd found so far is this one:
download it and on your image editor, just save it as PNG (the jpg tends to compress every time you save and trust me you won't want that)
after that, every time you explore a place, just mark it on the map with an X (or cover it with a box) and a line on the names around the map