This is an independent recommendation - I wasn't asked to post it, nor am I receiving any inducement for doing so.
In Shiraz we did two day tours with Pars Tour Agency - first to Persepolis and Parsegardae, secondly a morning tour of Shiraz city sights including the Eram Gardens, Hafez and Saadi tombs, and Quran gate.
I highly recommend Pars Tours for price and overall quality of organization and tour content, and especially Ehsan Deghan (+98 917 674 3048 or +98 933 163 3707).
Ehsan is a young tour guide with s passion for his city and its ancient sights, as well as excellent English, and a friendly, outgoing manner. He has his own car so can organise a private tour if you prefer.
Ehsan brought Shiraz to life for us, and even treated us to an ice cream at the end of our city tour.