This may be obvious but....
Move everything out of the way and pull out yer TV unit etc so its easy for him to get to so he can start work promptly (he may be running late and anything to save him time he will definately appreciate)
Also welcome him inside and offer him coffee/tea.
My sky engineer was absolutely ace, he wasn't a contracted out engineer, who even he had to have a moan about.
He answered all my questions and went above and beyond to get me sorted out properly:
* Installed quad LNB on my old dish as he wasnt happy with my signal (now get 2 full signal meters)
* Neatly tacked the cable from the box along the skirting to the phone and tidied up my adapters on the phone line.
* Explained to the missus* how it all works etc.
* Got a Samsung box which imho is perfect (haven't had any issues with it, sometimes I wonder what people on forums moan about them for)
*ok me too I admit
edit: He also didn't defile my porcelain, thats reserved for me.