Hi Jonesy -
I can add little to the Wisdom Bill imparts here, but as a VERY fledgling mandolin player I've taken some inspiration from one of Canada's premier mando-fiddlers, Ray Legere.
Ray is a very accomplished performer and studio musician who's been touring with Balladeer John McDermott lately. He (Ray) once filled in for Bill Monroe, so Bluegrass isn't a problem for him, but he's made a smooth transition to the Celtic strains with his back-up on such tunes as 'Wild Mountain Thyme' and 'Bluebells of Scotland'...
You might want to check out his web-site :
http://netshop.net/~rayleger/
Good luck and best regards,
Murph