5. Don't Get Over-Obsessed About Your Plugin Quality
The most frequent Internet search queries are "What's the best EQ?", "Which EQ should I choose?", etc. But, if you don't understand the basic EQ principles, it doesn't matter which EQ you'll use to get the same bad result.
Do not blame the plugins for all the troubles. Start from learning how to achieve decent results using the plugins your DAW has onboard, and then turn to more advanced and feature-packed EQs, which you definitely don't need in the beginning.
6. Don't Treat EQ as a Universal Problem Solver
Use the EQ only if you need to remove/cut out unpleasant frequencies, or to change the sound character add make it more interesting by boosting certain other parts of the spectrum.
If, for example, you recorded vocals onto your smartphone and try to improve it with an EQ. No matter how much you try, the result will never resemble a recording made with a high-quality microphone.
You can't cook a nice dish from spoiled ingredients. You better spend some money on a studio recording than waste your time and effort trying to "deceive the reality". If you boost any frequencies in such a badly recorded material, you'll only make things worse emphasizing its imperfections.
The same applies to the selection of sounds, samples and synthesizers. It is often better to just replace the sound, than to try an "EQ surgery".
7. Add Clarity by Removing Muddiness
The most problematic frequency range in many home-made recordings is 250-500 Hz. If you leave too much of such frequencies in your mix, it will sound muddy.
A smooth and wide 3 dB cutoff made within 250-350 Hz on muddy tracks is an excellent starting point for your further work.
8. Mixing in Mono
This is another method that could be useful in some situations.
Try switching the mix to mono when EQ-ing it, it helps to better distribute the frequencies and prevent phase problems. Also, it will enable you to focus on adding dimensions to your sound scene by using an EQ, instead of relying on panning knobs.
Having finished your mono session, switch back to stereo and continue with panning of the tracks. As a result, you'll notice your mix gained more space than it had in the beginning.
Mixing is the thing which you can never stop learning. Even the most successful and famous sound engineers in the world all the time discover different new approaches to try. Take it as our advice: have more practice and try more experiments. And most importantly: not only listen, but learn to hear too.