There are several different methods you can use
to master a CD. It's not the cheapest option but many choose to use
professional CD mastering engineers. Mastering engineers generally work in
their own facilities, which are usually different than recording studios.
Everything is designed specifically to get the best possible playback so any
errors can be corrected.
If you don't have the funds for this you could
try mastering at home using your own computer and some mastering software. For
any musicians or artists who are just starting out this would be the most
affordable option. The quality of the software and the skill of the operator
doing the mastering can make or break the mastering process. The difference in
quality between recordings usually comes down to the mastering. When you listen
to a tune on the radio it’s the mastering that gives it the high quality sound you
hear.
Unless you're really strapped for cash a
professional CD mastering engineer is your best option for generating interest
in your music.