If your final mix is good and doesn't require effects, just level modification for your output signal, use a program called T-Racks. Do all your effects in something like Wavelab (allthough it's not always great to place effects on the WHOLE final mix). but once you've finished with effects, run the wave file through T-racks and you can use the compressor or limitor you add the finishing touches to your track. You can use EQ to add a bit extra to your mix. I always find that raising the hi frequencies slightly always helps for the final mix to get rid of any mudiness if you unluckily get some. I also use the low frequency shelf just to get my bass sounds at a level that most monitors/speakers will handle. otherwise your sub woofers will rumble too much! hope this help. Really, to master your demo properly, it's a costly thing but worth it: buy a TC Electronics Finalizer. They're great.after mixing, i use them on all my cd's, and they're perfect. alterntivaly, send your demo to my mastering studio! we have all the gear you need!