If you want to set up your own studio it may be hard to quantify the areas which are going to be truly important and, in fact, one of the most important areas is often one which is overlooked.
The most important area will always be knowledge of how best to get the most out of different instruments and understanding how best to position microphones for optimum effect. However, the next most important aspect will often be the recording space itself, as good recording equipment is now so ubiquitous and easy to come by that anyone can create a studio at home with the right computer and some software. However, a knowledge of how to make instruments sound good and a space that has great acoustics are less easy to find.
Using drapes and acoustic foam to not only stop external sound permeating the room and showing up on the recordings but also to help create a more intricate acoustic setting is going to be integral. Very few garage bands will have a space they can turn into a full time studio and the cost of buying foam and drapes to transform a space is one that will pay off hugely. The space itself is often immaterial – instead, it is what you do with it that counts.
Understanding how best to hang drapes can be found out fairly easily online whilst foam suppliers should be able to give you a good idea as to how much of the material to buy and how best to position it depending on your own space. In turn, by going direct to foam suppliers it will also be far cheaper for you to get the right sound proofed acoustics too.
So, whilst anyone can buy a computer and some software, few spaces will have soundproof qualities and the right acoustics, and an investment in this area could be all you need to really be able to stand out.