Overall 6.5/10
Don't like the stripes all over the thing. Doesn't make sense to me.
The shadow on the Tehdalo is wayy too present, and doesnt make sense because you have light on a few letters coming from the right, when the shadow is focussing to the middle.
The skypelogo overlaps Skype, don't like the look of that.
The ":" is waay too low on there, can be the font but I don't like that.
If you want to mess with shadows make sure to:
1. Have a lightsource coming from the same direction the shadow comes from. Looks very unrealistic the other way around.
2. Don't make it too big, that gives off a very strong lightsource and you don't usually put such strong lightsources on an image.
3. Focus on the complete signature, if you shade the top text to the middle of the text, make sure to not use a different shadow, or none at all on the rest of the signature.
I may be excaggerating (lel grammar i haz it) but this will only improve your work.
Keep it up man! be sure to show us some progress