Steady hands.. a good fine tip soldering iron and FLUX. Plenty of rosin flux.
Heat the iron and dunk the tip in flux. Wipe off with a damp paper towel or a dampened soldering sponge.
stick the iron in the flux again and tin the tip (coat with solder... make it shine)
Put a little gob on the circuit board.. tin the spot if not a through-hole
Glob flux on the wire end and tin it.
More flux and make the joint.
Its almost impossible to use too much flux. Get a tub of it.