hammering forms - slow work - sonnet attempt 2

With free verse,putting words down isn't hard:
whatever comes to mind, I write. The speed
of writing lets me drop my critic's guard -
the product though, might not be worth the read.
With structured verse, the words are hard to find
and once found, often wrong, or weak at best
I mean this exercise to stretch my mind
but so far it's my patience that's most pressed.