Well,
that question is not that easy to answer,
it depends on how many boards you have to solder
and how much money you are willing to spend.

For a "single shot" or a low number of "hand soldered" boards:

use "solder" with a maximum diameter of 0.5mm
use an "iron" with a very small tip but enough power and Temp. regulagtion.
(Don't even try one of those "Soldering Needles" with only ~5 Watts)

My "Iron" has 48 Watts of Power, has a 0.3mm Tip, is Temp controlled and isolated.

I have done many boards with it with really good results.
(On my designs for "hand soldering" I'm not using any component smaller than 1206 or 150mil)


(I don't want to start a RoHS discussion,
but my experience so far is
that leadfree solders are not as good as the "old" ones containing lead)