Hey man. Those are so excellent advice. Mixing headphones and a nice audio card. Eventually you're going to need a nice monzonito system. As you get more advanced, you'll realize what you have is limiting and what you need now. it's not something that only practice, practice. practice, more practice, oh and did I mention PRACTICE will make you as perfect as you'd like.
Also remember to read a lot of the books like the 'Mixing Engineer's Handbook'. That helped me out tremendously and there's also a 'Mastering Engineer's handbook' - I could be mistaken on the name. But stuff like SOS and THIS forum will leave you sounding like a pro if you follow everything as they show examples of.
Doesn't matter if it takes 5-8 years or more. We'll get there