What I did, and still do for tunes that are tough for me to play, is just
concentrate on playing at a slowed speed (not necessarily dirge tempo, but slow
enough) and make sure that I don't do anything flashy or complicated, just play
the basic tune steady and on time. Eventually I'd build up to session speed, but
it shouldn't take too long to do. Once you can play it steadily in time at a slow
speed and work your way up, you'll be able to rip through them at playing speed.
I sure as hell know I'm not the most metronomically gifted either, and it's
especially hard playing such a bleedin' difficult instrument! :-)
Slán go fóill.