I did a few optional rules... I didn't use any Pokemart which made me really value the random pokeballs found around. No catchings or using Legendaries, since they are technically not the first encounter in that area. I also did not use my Master Ball.
Well with Repels you can get around that, but even still if someone uses a legendary during a nuzlocke they're a scrub. I just kill 'em and snag that free exp.