Producing modern vocals that sound crisp and clean is pretty easy these days if you have access to pitch correction software. Even without programs like Melodyne, Autotune, Wavetunes, or Nectar, you can still make your vocal mix sound WAY better just by using some common sense mixing principles like panning, doubletracking, compression, and EQ.
Most of my videos are theory based- this one breezes past the theory and writing to jump straight to production. In my opinion, the modern musician MUST consider production when writing his/her music, unless they strictly intend on only performing the music live. The more production knowledge a composer has, the more easily their songs can realize into the actual world without any hiccups. It also gives you a lot of confidence as a songwriter, knowing the sort of production techniques you intend to use when writing that can create certain sounds or cover up certain deficiencies.
I’ve posted a PDF of the 4-part harmony on my Patreon.

Music Production