Probably the biggest problem is the blank. From the looks of things, you used a hard eraser to get the dual type blanks together. Don't do that. Instead, use a an eraser set to 15% hardness to blend the blanks together. Also, I used to a very larger eraser size to blend the blanks together (I used size 300), and I only did one quick stroke.
On to the illustration, Celebi is really blurry, and doesn't look good. Also, the illustration should never cover up the "important" stuff. Looking at your fake, Mew's tail and Celebi's hand cover up the LEGEND text a bit, so you might want to erase around there. You're also missing a holofoil.
Finally, the text. I don't know what happened here. The text should be the same settings as a regular fake, except this time only all white. You should also enter your text and then rotate the text box to get the LEGEND "feel".
All of this aside, it's a great start to faking LEGENDS!