There are no forks to fork...

I'm studying tactics until they are running out of my mind  - queen forks, knight forks, bishop forks, even pawn forks.

But in my games I have only done a very few forks (and have only been forked myself a few times.)

When I look around to fork pieces, they are all protected.

Discovered attacks I find. Pins, yes. But forks, no.

What is your experience with being able to use all the tactics we are studying so hard?

stwils

I just won a queen with a knight fork, so it certainly happens. It can help to bring your knight to a strong square on the fourth or fifth rank.

If a piece is attacked once and protected once, it is essentially loose and subject to a fork. 

You may have to "nudge" a piece onto a "forking" square.

Alternately, you may try a "removal of the guard" tactic prior to a fork.