You will not pickup all that is needed on this or any forum. I suggest looking for a manual , book or DVD on airbrushing models.
Check out guys like Bob Downie, Pat Covert or Donn Yost.
All of these GURUS give facts not fiction and an investment in any or all of these helpers will be worth every penny spent. I thought I knew a lot due to my 1:1 painter friends.....NOT!!!! You can do as Marcus says with practice....I like to have a safe starting point
Good Luck!