For 30 years I thought I just instinctively knew where to put speakers in a room, then I found the Cardas formula; I did the math, moved the speakers to the recommended locations and the sonic image snapped into place to another whole level.
Be aware however, once you start on this route you are on a slippery uphill slope. You will find that the ideal room as certain length, width, and ceiling height ratios, and you may find you need more length to support your desired lowest frequencies, and you you might need any number of acoustical treatments, not too mention software spectrum analyzers and other tools. At the end of this journey is a realization that as important as you thought the room was is the discovery that the room has a HUGE impact on the final sound - and all the great gear in the world isn't going to overcome the wrong room. If you happen to have a good room on the other hand, you are on the road to potential sonic happiness. Good luck.