First one:Let's start with the render:
Or you changed the opacity, or you changed the blending mode.
It's too transparant.
The size of the render is too small compared to the canvas of the whole sig.
Change the size of the render or the canvas.
The text isn't bad, but it distracts. The vocal point(s) should be around the render and not at the text.
You could reduce the size of the text + play with the blending modes and opacity.
Another thing you could do, is add a border.
Even a simple 1 px border can be nice.
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Second one:The canvas is just a little too big, because you have an empty space at the left and right side.
Change the size of the render or canvas.
The render is blended in ok, but could use some improvement.
This is just practising.
I see the vocal point is at the hand.
If you compare the hand to the total size of the sig, you'll notice the size of the canvas is too big (as I said before).
You could also work on the depth in this signature.
There is barely any depth.
A simple way to add (more) depth is by blurring the background and sharpening the render (not too much).
The text is ok.
Something else:
Always look at the shadows of your render. Adding a lightsource (or more lightsources) to give the signature a more realistic look.
Keep practising
