Soldering Single Row Headers

Trick:
Slightly bend the inserted portion of the pins at the end of the row you are soldering opposite directions. Usually perpendicular to the row.
Here is an ASCII representation with them bent parallel to the row. Notice the short end is bent as we are using these as wire-wrap posts.
Ex:

||||  /||\
----  ----
||||  ||||
||||  ||||


This way the header doesn't fall out when you try to solder it from the other side.