I'm a little confused about when it is appropriate to cut flowers. In
particular, I planted what's called a "Tickseed" Coreaopsis Grandiflora
(according to the label). It's a flowering perennial with golden flowers
and it's already flowering. Should I wait for the flower to wilt or
should I catch the flower in full bloom and cut it? I'd like to have
this thing bloom all summer long if possible. I have a few other
perennials like this too.

Also, is this what you've been referring to as "Deadheading?" It says in
the planting instructions: Deadheading spent blooms promotes flowering.
So I assume that means cutting the dead flowers but I'm not sure and I'm
getting tired of learning through mistakes.