Hi Michael
How it is done in industry is you make a solder mask(which is a metal plate with holes same shape as the pads) a machine places this plate acurately over the pcb and puts solder paste on top of the plate like printing with a silk screen. then after the metal plate removed you get pads covered with exact amount of solder paste.
Then the pick and place machine picks the SMT components from reels at extremely high speed and places them where they should be, the solder paste makes them stick (in the old days they used to have glue drop to hold the components down) then they go to the hot air oven where all components get soldered at the same time. After that visual and electrical inspection.
You can do the process manually but you get the disadvantage of low speed and high error rate.
I visited a factory in south africa and seen the machines in action, very interesting to watch.
Regards
Mahmood