Anyone here experienced with mastering?

[feedingear]

reference reference reference. a good master cannot save a bad mix. mastering is kind of like adding icing on the cake. you can use it to clear up some weaker elements of a mix, and to enhance the good stuff, as well as to give the track a coherent colour (across an entire record).

To give you a VERY brief and simple rundown, most track masters will include EQ (very gentle enhancements or shaping), eq to look for any resonant freqs missed or disguised by the mixing environment, possibly mid side processing depending on the track type and requirements with their own compression and eq settings and comparative level balance. Returning from MS you may then apply more compression - simple, multiband, as well as parallel compression can all be set up at once. again, its usually very gentle and minimal processing done at every point in the chain. Then you might do a bit of outboard processing through analog gear to try and colour the sound by introducing 2nd and 3rd harmonics, and then finish off with a limiter/dither if 16bits required.

Thats a bastardised version of what happens, but if you follow that chain on a finished wave of your own tracks you might start to see how you can enhance/correct a mix with mastering.