Well myself as an amateur producer! I haven't gotten into mastering my work! BUt one thing that has definitely helped me volume wise is recording every instrument as loud as possible without it clipping and being distorted! Like for example, piano; bang on the keyboard until the level is clipping in the software! ONce you lay It down you'll be able to turn it back down in tif mix and have plenty of head room later while mixing! If this doesn't help, then try a mastering software!!!
