Mixing is tiering.

[jasedee]

Try to keep the level constant!

I think it is recommended listening at around 75-85 dB SPL (For up to 8 hours listening) to be at safe levels. Dont let your hand crank the volume as you get fatigued....take a break, go outside, give your ears a rest.

Give yourself a point of reference. What is the most important part in your song? Is it the beat? An awesome synth line??? Figure it out, and mix other instruments around this part.