Soundproofing your room can be mighty expensive for aspiring sound engineers and music professionals. I remember being specifically weary about the failure of placing soundproofing materials in the correct spots for maximum effectiveness due to lack of experience, engineering knowledge and simply being unsure about how to combat the plethora of acoustic problems in my mixing room.
I came across the Auralex Free Room Analysis - http://www.auralex.com/praf/. You can submit a detailed sketch of your mixing room/studio on graph paper for those who do not know how to process outlines on architectural software programs for detailed analyses. Auralex’s engineering professionals will then review the sketch submission and show you how to soundproof your room absolutely FREE using their products. If you decide not to use Auralex - At least you have an idea of where to set up bass traps, acoustic panels, density curtains etc. There are plenty of options on the internet that can provide the same function for sound absorption ,but I highly recommend Auralex for their industry standard acoustic foam. Receive a second opinion from a sound engineer as well - I really believe that Sweetwater Sound has pristine customer service, engineering knowledge and goes the extra mile to make sure you are taken care of with plenty of different acoustic options.
Roxul Wool is a great alternative for those on a budget who like the DIY approach to setting up a studio.
Make sure the Noise Reduction Coefficient and Sound Absorption Average is close to 1.00 or higher for maximum frequency deadening.
NRC - The Noise Reduction Coefficient (commonly abbreviated NRC) is a scalar representation of the amount of sound energy absorbed upon striking a particular surface. An NRC of 0 indicates perfect reflection; an NRC of 1 indicates perfect absorption.
SAA- The SAA value is the average of the sound absorption coefficients at twelve 1/3 octave frequencies ranging from 200 to 2500 hertz.
This analysis will help you get the ball rolling for people who are uncertain where to start in terms of providing acoustical treatment to their studios - http://www.auralex.com/praf/
Please let me know your thoughts or any ideas to gain a better understanding of your room to gain the best possible result in acoustic treatment for your studio!