I think you have to learn to walk, before you can run. Many of the singers you seem to like are able to engage audiences with tricky rhythms and songs which are difficult to sing - or even to remember the words, being long and complex.

I'd say rehearse these difficult songs - pay particular attention as to how the singer punctuates the lines, manages his breaths, keeps the narrative flowing, emphasizes certain words and phrases to punch out the rhythm,or the story. At the start though, do it at home, when you're in the car driving, run through it in your mind in the doctors waiting room.

When it comes to performance - give the same level of attention as to how good singers involve an audience with an apparently simple song - how he times the lines, and pitches the song at the audience. Anyone can do it badly and most people do - its only superficially easy. The recording of Peter Bellamy doing Yarmouth Town is a master class in this. A simple song, but he takes the audience with him ....oh SO cleverly!

When you've got the hang of that - try one the tricky ones = somewhere where you won't piss too many people off. Nothing clever in boring the arse off everybody. People say you're keeping the tradition alive by just singing folksongs - not true. Folksongs (trad or contemporary) are at their best, high art and they need whatever performance skills are within our feeble grasps.