A couple of groups I know pick their first 3 tunes, and then decide what to play after that on the fly. Sometimes the same 3-4 tunes usually get played in sequence regardless of where they are in the set.
It's interesting to see what other folk are planning to play, (and I'm taking notes for tunes that we could add but haven't had the time or inspiration to practice.)
Here is the list we roughed out for the listening pub as sort of a compromise between lively and quiet, since the pub owner specifically asked for uptempo music. The "*" tunes are 4pt acapella, and yeah, they're not all irish, but neither are we.
DonkeyRiding*, AsIRovedOut, StAnnesReel/CollegeHornpipe, GypsyRover, GreenGrowtheRushes, LittleBeggarman/HarvestHome, Colcannon*, LoftusJones, HillsofConnemara, MaidDeepinLove, LevelPlain, TellMyMa*, PhiltheFluter, IrishRover, CalonLan*, Newry Town
We're planning noisy mainstream stuff for the second gig: BlackVelvetBand, DannyBoy, DrunkenSailor, ... WhiskeyintheJar(gotta dig the Metallica version), WildRover, maybe throw in some jigs and hornpipes to give voices a rest.