1. Use a good set of mastering tools. There are many different mastering tools available, so it's important to find a set that you're comfortable with and that gives you the results you want. Some popular mastering tools include iZotope Ozone, Waves L3 Multimaximizer, and FabFilter Pro-L 2.
2. Start with a good mix. Mastering can't fix a bad mix, so it's important to make sure that your mix is as close to perfect as possible before you start mastering.
3. Use your ears. Mastering is as much an art as a science, so it's important to use your ears and listen carefully to the music as you're making adjustments.
4. Don't overdo it. It's easy to get caught up in the moment and over-process your music, which can actually make it sound worse. Use moderation and be careful not to overdo the processing.
5. Reference other tracks. It's helpful to listen to other tracks that are similar to yours and see how they're mastered. This can give you a good idea of what to aim for in your own mastering process.
6. Get feedback. Once you've finished mastering your track, get feedback from other people to see what they think. This can help you identify any areas that need improvement.
7. Experiment. The best way to learn how to master audio is to experiment and see what works for you. Don't be afraid to try different things and see what sounds best.
With practice, you'll be able to master audio like a pro and get your music sounding its best.