6: EQ and separation:

This whole process is an art unto itself, and there is no hard and fast method that will ensure you get a clean separated mix.
Here are some hints and tips though.
Visualise your mix.
I see the mix as a side running bar chart. (This is just my example, your own mental picture should be something you yourself can visualise) with the sounds running from top to bottom on the chart, top being the high end, bottom being the bass frequencies. As in the diagram.



The bigger the sound, the thicker it is on the mental picture, and visa versa.
The object is to cut and fit the sounds so they fill the graph from top to bottom, but overlap as little as possible.
Placing the sounds visually in your head makes it a lot easier to separate your mix.
I also split the bass mentally into 3 bands. Low bass, mid bass, high bass. And the same for the mid range and the top end. And then mentally picture where each sound lies.
May look a bit or sound a bit odd, but drawing a mental picture really does help a lot.
Oh as an aside the EQ process I use and you should always use for mixing is Subtractive EQ. Something that has been discussed loads on here, but I`ll go into it at some point.