im sure by now you have fixed your problem but for anyone else who is interested
put simply its a multiple stage process
firstly the tracks should be [b][color=#b22222]mixed well[/color][/b] - also [b][color=#ff0000]no clipping[/color][/b] should be seen/ (heard) on any tracks
secondly the master fader should be left a [color=#ff0000]0db[/color] never touch this however you can add [b][color=#ff0000]EQ, compression and limiting[/color][/b] to this master fader.
this will both stop the clipping and make the track louder however it is important to understand the audio capabilities in software for your movie, audio engine, game engine etc.
finally [color=#ff0000]listen to your track on multiple devices[/color] then mix it again this may need to be done 2,3,4 maybe 5 times un-till you get the balance right.