For your second attempt it was a lot better than mine:
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Remove the text, the boarder and the Drop shadow you've added to the boarder.
A good tip is try not to center your render. Choose renders that have action and flow in them. Such as this one:
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you see the direction of flow there? going from bottom left to top right, a lot of that was helped by the render itself.
Lighting is tricky to get the hang off. Most/All new users go for the soft brush light source from the top right/left, and more advanced users use that too. The best way to create good lighting is with the dodge and burn tool. The dodge tool makes the bright parts brighter, and the burn tool makes the dark parts darker. Once you've got your lighting correct, you'll notice a big improvement in the tags depth.
If you need some tutorials I can show you a good few that will help you

Keep up the enthusiasm and if you need any help feel free to ask me or another member of the uG~ family :y: