First attempt at a signature. [UPDATED]

For it being your first attempt at making a signature, I would say it's not too bad. I think your main problem is your over use of overlaying filters. Depending on the colors and textures of the images you want to blend together, sometimes too much blending just creates darkness. That is especially prominent in the Randy Orton graphic. I had to turn my screen brightness to it's highest setting (I'm on a 2012 model iMac) in order to notice the 'RKO' text. With that being said, however, the RKO font looks like a good choice and good placement. There's good composition in both pieces actually. In the first one I don't like the text that's almost hidden down in the bottom left corner. It's way too small and I honestly looked over it at first. I wouldn't have used a black font either. I can't tell if you put an outer glow on the text because it's so small but I would have used a lighter color text and used different techniques to bring out the text other than a glow. I think a lot of people feel like using black fonts are the only way to make a bold statement with the text. There are so many cool colors in the background that could have translated back into the font color to make it a lot more interesting. I would definitely go with a brighter hue in the color choice though and set it off with multiple strokes. When you add multiple strokes to text, it can be a really good and easy to way to make text work look professional and clean. A lot of fonts look completely blank and boring when you download them and try them out. It takes a lot of customization to really make the most of your fonts and text work is very important to graphics. I would say it's a decent start for these being your first works and I would definitely encourage you to keep experimenting with new ideas.