Ford... repeat to yourself... heat the joint, heat the joint... same as plumbing... you want to heat both sides, solder runs to the hot side. With electronics, shiny is good, dull is a cold joint, and unlike plumbing do NOT unnaturally quick-cool the join (like with a wet rag)... and use rosin-core or straight solder for electronics - not plumbing acid-core.

Bren R.