The main thoroughfares are Talaa Kebira (Big Slope) and Talaa Seghira (Small Slope), running roughly east from Bab Bou Jeloud, converging near Place An Nejjarine, and continuing to the Kairaouine Mosque. These two streets are lined with most of the historic buildings, major markets and other sightseeing spots.
To navigate, use the medina's setting in a basin. The lowest point is Place R'cif, and if you head downhill, you can get 'out' there. Uphill will lead you, eventually, to a city wall and a major gate.
The gates that most tourists use happen to go in alphabetical order clockwise: Bou Jeloud on the west, Guissa on the north, R'cif in the centre and Ziat on the south side. Two other major 'exit' points are Place Batha and Ain Azleten, which has a large parking lot.