Being honest im still having trouble learning the mastering process. So my comments probably arent all that relevant.

i will say that i agree with mark that the mastering process should be seperate from the the mixingdown and creative process. Catching the buzz is important when creating a track and a fresh pair of ears is useful for EQing and making the track listenable.

Using a great EQ and multi-band compressor sparingly seems to work for me. However...

I still have a long way to go (possibly forever more..) before i can be happy with my ability to master for different formats, there is just so much to learn and getting my ears "into the right mode" is most definately a slow process and one that i think is probably only gained through experience and practice.