Once you have an understanding of the type of solder needed for an application, (a hard solder such as AuSn for reflow temperatures above 125°C or a soft solder such as SnPb or SnAgCu for lower temperatures) it is time to consider the impact of the substrate metallization on your solder choice.
Common surface finishes for soldering include gold (ENIG), copper and OSP, immersion silver, tin, and nickel. Each element reacts differently with these finishes and solders should be carefully chosen to match the finish to prevent issues such as brittle intermetallics and excessive scavenging.
The data sheet titled flux and solder compatibility found here recommends solder choices for various substrate finishes as well as incompatible solders.
For more assistance in choosing an appropriate solder for your particular application, please feel free to contact me directly.