Do: High pass anything that you don't want to have bass at 100-120 Hz (or higher! Use your ears.)
Don't: Forget to have a separate sub for your basses (it's easier than having to try and mix the sub from five different synths!).
Do: Listen to tracks that you enjoy and try to analyze the various components - How long is each section? What instruments are being played, and what instruments are playing the melody/chords/bass/rhythm? How many instruments are there? Does anything special happen at the end of every 4 bars? 8 bars? 16 bars? What happens during transitions? etc., etc.
Don't: Compare your progress to that of other musicians! Everyone advances at their own pace, and everyone has areas they wish they were better at. Keep with it!
Do: Pick one to three synthesizers and figure out every single thing there is to know about them. Try to create sounds you know where made with them, and try to create sounds you know weren't made with them. Explore presets and reverse engineer them! Become the master of those synths.
Don't: Chase the gear! It's very easy to get caught in a VST-hole (I'm a victim of it myself), but you need to know the fundamentals of synthesis and you need to be comfortable with ONE synth before you try to learn ten more.
Do: Spend a month or two doing nothing but clicking every little thing and opening every little menu in your DAW and asking "what the heck does this do?" If you learn the ins and outs of your working environment, you'll never get lost when in the creative process.
Don't: Forget to read the manual! Instruction manuals are an essential learning tool, in my opinion, for getting the most out of your equipment. You'd be surprised at what secrets the developers may inform you about.
More to come as I think of them.
