Just keep at it & it'll become second nature to you. I no longer do signatures myself anymore. Much older now & life priorities take up a majority of my free time. I started with Corel Draw 9 back in 1999. I was terrible but I stay committed. I would move on to Photoshop with version 7. Once I made that move, that's when my designs really took off. The last Photoshop I used to make a signature was CS2. I do still use Photoshop but I moved on to photography. Your designs are fine & it is okay if you receive some criticism. As long as it is constructive. Don't pay any mind to any negativity that some community members may cast down on you. You keep grinding away & I'm sure your work will greatly improve!
Edit: As a confidence booster, I'll show you how I started.
I went from this (1999-2000)
http://i213.photobucket.com/albums/c...s/gokucopy.gif
http://i213.photobucket.com/albums/c...s/darksig2.jpg
To This (2004 & 2007)
UT2004 Clan Sig
http://i213.photobucket.com/albums/c...igcomplete.gif
FFXI Guildie Sig
http://i213.photobucket.com/albums/c...s/fr0stsig.jpg
-LatinLegacy