I have a small "L" shaped listening room; thus, I have a near field setup. My room is 11'-5" wide; long wall is 28'-2"; short wall is 15'-7". My speakers are 2'-5" from the side walls; 4'-0" from the front wall; 6'-10" apart; and toed-in about 3/4". My listening position is 13'-5" from the front wall, i.e., 9'-5" from the speakers.
I spent a lot of time on Agon researching this topic and tried many different things trying to make my speakers disappear. I finally purchased Paul McGowan's Audiophile's Guide. I found it both informative and very useful, and it helped me dial my system in. By that I mean, depending on the music source and qualify of the recording, my speakers may or may not disappear; my soundstage may or may not be wider than my speakers; and I have not yet used any acoustic treatment on any wall.
For the price of a book and suggestions found on Agon, and a lot of moving the speakers and sitting position, and adjusting the toe-in, most of the time my speakers do disappear. I think the book helped the most. I'm quite happy with my current setup.