I want nicer 2nd/3rd day curls! Any recommendations?

[WhyZed]

I have long naturally curly hair that doesn't need washing more than once a week. However by day three the curls are sort of flat or have just gone. What can I do to revive them without needing to wash it all over again?

Spritz with water or (depending on texture/dryness) water + conditioner?
My hair isn't curly but if I want to encourage waves I spray it lightly with distilled water, push it into the shape I want, air dry - works a treat. I'm sure filtered or spring water would work as well, we happen to have distilled in the house but hard tap water doesn't have quite the same effect.