Everything in this post has already been said somewhere, but as it is all together in my head I thought I would dump it upon you unassuming readers
I've started working using a new method lately, and it has helped my mixdowns and "personal masters" immensely - just thought I'd share:
1.) Start with your track faders at -6dB - NEVER at 0dB, and keep your original sound sources individually below the -6dB level of track volume.
2.) Turn the volume knob on your speakers/stereo system/headphones up so that it is twice as loud as normal, but still mix to the volume you are used to - which makes my previous statement about mixing with track faders initially at -6dB make more sense - the combination of the two will cancel out - and initially everything will sound how you are used to hearing it.
3.) When you bring in any reference tracks you are trying to "sound as loud as" - bring them in as audio tracks turned down to -6dB.
The effect of all this apparent weirdness is that you will begin to ACTUALLY mix your songs ( in a much more similar way to how it used to be done on analogue desks ). Instead of mixing to the reference track at full volume you will be matching it at a lower volume, avoiding squashing the life out of your sound.
Once you get them matched nicely at -6dB, begin to match them further and further up the scale, until eventually you get closer to matching the reference track at 0dB.
Start without anything on the master track - no limiters etc, and start so your song never exceeds 0dB - if it does turn down your track faders to make it quieter - at all times leave your master fader at 0dB.
You will find "mastering" ( imo send it to a mastering house, or you will never be able to get "that" sound you are after, you WILL get close, but their is no replacement for the experience of an expert ) after this a lot easier, as it will be easier to get the initial vibe going, as you are mixing with much more headroom and your initial mixes will be able to attain much more punch, dynamics and clarity.
The other key thing you will learn is that matching the quality and presence of a professionally mastered track at a 0dB peak reference level is nearly impossible - as this should be reserved for the profession mastering engineer. The other thing to learn is that if you DO send your material to a mastering house mixed with the suggested method here, do so without increasing the volume level, so nothing exceeds 0dB, as a 32bit at at least 96kHz sampling rate - or whatever is their preference, as an uncompressed file, and the mastering engineer will be a very happy person with plenty of room to make your material loud and lovely.
Seriously, you really must try this before you say it sounds weird - my mixes have never sounded so good since I started doing this, and it's essence harks back to the days of analogue mixing. Have fun and try something a little different, and when you do really want to make your tracks loud, you will find mixes initial set up with way will respond very well to limiters. Something about this method sets the track up to be squashed much more than normal with squeezing the life out of your mix.
Another thing is learning to side chain deep percussive hits - i.e. kick drums - against your bassline. I used to think this wasn't necessary - but now I think even if used with only a few dB max of gain reduction, that it is. The new Live 7 inbuilt compressor is surprisingly good at this, and once you get used to this you will find that squashing your bassline when the kick hits makes your kick sound more punchy and also reduces the overall volume of your song, whilst maintaining the same perceived volume - allowing you to go even louder at the mastering stage.
Aside from that remember that every instrument, in order to be heard in its own right within a mix, needs its own space. A slight decrease in the high and low frequencies of each sound, centered around its "key" frequency will help maintain the individual space of each instrument. A tiny amount of this does wonders to your mixes.