I'm testing a flying loom using a DSUB-9 serial cable:
try to
- push the wires into the pad (cut the extra part on the other side, if necessary)
- use the right temperature and time when soldering (so insulation is not melt, but soldering is fine)
- ask for someone's help. It takes much more time to do it nicely alone
- make sure no hair is tangling - that will short sooner or later
- use hotmelt after testing, to prevent damage
- also cut short and insulate the hair from the cable shield