Your sample image was most likely created in Photoshop. Photoshop makes the inset rectangle a bit easier, but the rays more difficult to make. Either application will work though.
- Draw one ray, a triangle. Wide at top, point at the bottom.
- With the triangle selected choose Effect > Distort & Transform > Transform
- Once you have the rays, you can either choose Object > Expand Appearance and then delete the rays you do not want. Or you can create a clipping mask to simply hide the rays you do not want.
- Fill the rays with a gradient of your choice.
- The background is merely a gradient filled rectangle.
Inner shadow around edge
- Select all, Group (object > Group), and then choose Effect > Stylize > Inner Glow and adjust the setting.
Lighter part in the middle.
This is simply a rounded rectangle with reduced opacity. There is a slight bevel effect on it. This is easily done in Photoshop but takes quite a few more steps in Illustrator. Essentially you want a dark stroke at the top inside edge of the shape and a light stroke on the bottom inside edge of the shape.
- Use the Rounded rectangle tool to draw the rectangle. Or simply draw a standard rectangle ad use Effect > Stylize > Round Corners to round the corners dynamically.
- Fill with a simply dark to light, top to bottom gradient
- Choose Effect > Stylize > Inner Glow and adjust the settings to your liking.
I didn't address color anywhere. The colors are all merely gradients. There's nothing special about how the color is applied to anything in that image.