It’s amazing how so basic a task can have so many variations.
Here’s mine for what it’s worth.
One of the many neat tricks I learned from GIA was that of
dipping my solder into flux before placing it on a preheated
piece. I almost never have to add more flux to the piece. I also
found a 2" round piece of flat plastic material, translucent
white color, (at the recycle store in the Boston Children’s
Museum) which I marked on the back with a sharpie to divide it
into 4 quadrants. The quadrants are marked “S”, “E”, “M” and "H"
for super easy, easy, medium and hard. I put a drop of flux in
the center of the circle and my solder chips in the appropriate
quadrants. If I need more flux on the heated piece, I dip the
side of my tweezers into the puddle in the middle and use them to
carry the flux to the piece. Heat doesn’t bother the tweezers
and their rigidity gives you control over where you put it. Added
benefit: an 8oz. bottle of flux lasts 4ever.