i was thinking to post something like this in thread, but since you've started on i'll add to yours.
First, your flies certainly show improvement, and you're right, it is gratifying to see the work you put in at the vise pay off after an extended period.
For me, they biggest difference is in my classic flies. I started tying them exactly one year ago, on December 3 2011. I started with a Jock Scott Salmon fly.
Here it is.
Then i tried a winged wet from Ray Bergman, the Fontinalis Fin
Neither were very good as you can see.
I put in a LOT of time over the winter in Jan/Feb/March learning techniques i thought i new and perfecting them. In May, after a gift of a hook and preformed wings from a forum member, I started tying Rangeley style streamers.
This was the first one, no particular name, just a made up fly based on the wing assembly i got.
Over the past year i've continued to work at the flies, adding to my skills and trying to get everything to fall in to place.
Here are the latest flies i've tied from each area
Winged wet - A freestyle fly
Hopefully this post will help the new tyers see that is a marathon, not a sprint.
If you want to improve, be consistent, tie often (I try to tie at least one fly or part of one fly every night) and ask for help. Don't be bashful about posting flies, because the only way for someone to critique your fly is to see it.
My winter project this year is Dry flies....should be a fun journey.
Finally, tying should be fun! If its not, then stop; if you get frustrated tying a fly, take a break, 30 min, 2 hours, 1 day, whatever, then go back and you'll see the same fly from a different perspective.