First, you should have an ambient to reflect on glossy materials, second, objects should have rounded, beveled edges, so that corners can reflect and get highlighted.
After that and when you can see reflections easily, you can tweak the glossiness of the material, or even mix two of them with different roughness.
The roughness of diffuse materials is intended to get an Oren-Nayar type material, aka more rough than Lambertian, that’s not what you want, so, leave roughness of diffuse to zero.
A shader mix factor of 0.1 means 90% of diffuse and 10% of glossy, moreover your object is black so its diffusion should be almost zero. Try inverting the ratio or such.
If the object has to be smooth and glossy then the roughness of 0.2 for glossy shader is quite too much.
Edit: At now, you will not obtain any glows of light in cycles without compositing.
Thanks Paolo, but how would I get an ambient light ( and moreover do I add one to my already existing light? Or replace that light with the ambient one? ) Also I already have the edges bevelled to 0.010.
And after a little tweaking I have the following:
mix factor: 0.100
I’ve probably got everything wrong but I do however have a little reflection but it’s more of a matt reflection than anything :L
You get matte reflections, maybe, because jour object has flat only faces and they are reflecting lights only.
With ambient I mean something around; it can be a background image set as world texture or real objects in the scene.
For the first option, in the node editor click on the world icon on the header, then add a Background shader and link it to the Surface input of the World Output node; add an Environment Texture, link it to Background Color input and choose a proper image to surround your scene, better an HDRI so you get whole correct light from the texture and you can enlighten your scene by it and/or add other lights as you please (but to the aim of tweaking reflections, also a JPG would suffice).
For the lights type in cycles, the matter is complicated, as a general rule, use a mesh plane (4 vertices), put it in the proper place and assign to it an Emission shader. Its size will determine the hardness of shadows. All that you can tweak in realtime preview, and adjust strength, position, size, etc.
As for your last parameters, as I added too late to my reply, glossy 0.5 is very rough for a glossy reflective material, but I’m sure that when you set up the right scene (only for testing also, if your actual scene is not suitable for that), you will be able to see these things by yourself.
Sorry for my bad English, feel free to ask if you don’t understand or in need of more exhaustive responses, I will do my best but
I trust in skill of so many users here.