How do you pronounce the spanish word jefe?

The standard Spanish pronunciation of "j", "jota" ['xota]sounds like the Scottish English "loch" or in German "ich". Sometimes it tends to be stronger [χ], especially in emphatic speaking. Example:

Trabajar [tɾaβaxaɾ], [tɾaβaχaɾ].

The other sound [h] as in English, is more dialectal.