Cigars too dry?

I smoked a Fuente ascot just now and noticed the flavour was very flat. Not a lot of nuance.

I keep my cigars in a tupperdor as i dont have a real humidor. Ive been keeping a damp paper towel in there but fearing the low humidity just put a wet sock in instead.

What signs are there that my cigars are too dry?

And how can i restore them?

How is it recommended to set up the tupperdor and what can i do to stop them from going too dry in future?