I'll assume that he's referring to the fittings with pipe threads on one end, and A/N fittings on the other that are screwed into fuel rail, fuel pump etc.
If that is the case you want degrease the parts and then apply an anaerobic sealer with teflon like the SWAK that demon seed recommended.
I personally use Permatex 80631
When you apply the sealer, do not apply it to the very first thread.
I'd avoid using teflon tape. You have to wrap it counter clockwise and it tends to ball up and not make a good seal.
Regards,
Joe Dokes