Solder heat dissipation
The easiest way to get the PCB soldered by hand is to heat it up to 50-80°C so that your soldering iron has less heat to provide. The best way, in my experience, to do this is to use a heat plate. There are special heat plates sold for soldering, but basically any that you can reasonably well control would work. Word of advice: because the PCBs you get are not humidity controlled anymore, do not heat the PCB up too much (i.e. going over 100°C) without first drying the PCB at around 50°C for a while. Otherwise your components will go *pop*.