so the camera is IN the room looking OUT the window.. thats tough.. lots of light issues..
Youll have to light up the subject like crazy to compete with the outdoor sun.. if you can shoot on an overcast day better, but not as pretty.. unless its nice and dramatic.. but that up to you..
Also your indoor light will need to be balanced to outdoor (or vice versa) in fact balancing the OUTDOOR light will lower the overall level of the outdoor light coming in the window further helping you to light the subject.
Its the LIGHT reflecting int he glass your worried about right.. ?