Study Curve

for me its having a good ear and listening to it carefully but if you are new to it you should like try to learn it and go to school for it and some they maybe u could be a pro

I've spent hours upon end in GarageBand and with music theory, and I think a lot of it comes naturally. It might seem obvious, but the conventions of music theory sometimes serve as constraints for creative expression--that is, if you play by the rules and stick to the principles of what is defined as "right" and "wrong" by music theorists, your music will likely sound dry and unoriginal.

I think what works for me, personally, is to just play with notes and keep moving them around until they sound good to YOUR ear, regardless of what "scales," "notes," and/or "keys" you're playing as a whole.

The answer could vary between whomever you ask, but if you were to become a music major you would have so much music theory that you would end up hating it. Based on specific scales and different modes pleasurable or distasteful tones are produced. If you take a look at classical music, you can break it down to each note and its progression, just like breaking down a great piece of poetry. You can actually train your ear to learn these sounds. I took a Music Theory/Ear training course once, and it was one of the most difficult classes I have ever had. I had 16 years of classical music instruction previous to that class as well.