Being blocked isn't just some kind of work stoppage. There are links all throughout artistic life: mental, physical, emotional, even spiritual. It's physically harder to make sensible lines, or even colour inside them. I find myself making rookie mistakes, like spending 15 minutes painting on the wrong Photoshop layer. It's a downer, and you never know when it's going to end. Unless today is the last day of my life, though, it does end.
My belief is that practise and more practise are what is needed to break past a block. Very accomplished artists never seem to be affected by blocks. Maybe they are just more professional about keeping blockages from public view. What practise has taught me is that an artist's life can be spent in a few distinct ways:
Evolution
Devolution
In a rut
On the edge
Apathetic
In ignominy
Blocked
In a groove
Slotted in
None of these states is permanent, unless you fall off the table and quit the game, or you get lucky and/or good enough to fall deeply into the slot. I made a drawing to explain my two-bit psychoanalysis:
Creative identity is like pushing a small ball up a tilted tabletop using a drinking straw. The more you push, the more you evolve. Stop pushing, and the ball rolls backwards: devolution. Fall off the edge of the table through inattention, and your career ends in apathy or ignominy. Learn to say, "Would you like fries with that?"
Carved into the tabletop are many comfortable ruts. Unfortunately, following a rut to its conclusion is not helpful. In the middle of the table is a large block that stops upward forward progress. Get the ball around the block to evolve. Maybe try living life on the edge. Don't fall off, though, it's a long way down!
Aim for the groove. Producing art when in the groove is awesome! Everything works, eveything goes well, it's a blast... but it doesn't last. Hit the block, and even the groove comes to an end.
Theoretically, the best is to get slotted in, that golden, glowing, magical null-gravity zone. In the slot, you've created an environment where you can't fail. It takes a lot of persistent work, or amazing luck, but some people manage it.