Some notes on my website say
'The multiplicity of variants of traditional songs fascinates me but I sing anything whose content feels right. The song must be worth the effort, worth the singing for its story or message or emotion. I sing some well known songs but only if something there has grabbed me.'
I have to 'believe' in the song even though I may know it is fiction; akin to watching a film or reading a novel. When I sing a ballad I'm watching it happen because if I can't picture it how can my audience. I have to believe IN it.
If you're lucky enough to hear Alan Prior sing 'The Star of the Bar' you will believe HE was the man in the song he is singing. HE drank his way down Rose Street in Edinburgh! Listen to Jon Boden sing 'Courting Too Slow'. I believe HE was the man who lost his love to the sailor.
By no means can every singer put across a tale like this but for starters you must believe it yourself.