The intro is my style, you need more reverb on the strings. The drop, the mix is off, sound clear but the bass needs to be louder in the mix and everything else needs to be brought down.
Oh yea mastering, ummm, I don't know how to master but take the loudest part of you song, it should be the drop, and use some comprssion.(what program are you on?) Turn the threshold to nada and let the song play, slowly bring back the threshold until the track is being compressed by two to four db. Then adjust the gain of the compressor until the compressed track sounds the same as the compress in loudness. Slap on a maximizer and adjust the gain untill it is loud. This will make your track louder but will add distortion.
Dynamic range sounds better but louder is normal with commercial tracks. To get the best mastering results I presume get a pro. If not have fun doing what you want.
