I highly recommend reading my Specular Reflections tutorial first, as it will discuss what a specular reflection is and more physics and theory on the subject.

Reference

Software Agnostic Material

The basic ingredients are as follows:

• Shading: GGX Shader
  
• Color: Almost black Diffuse Color, remember the more specular reflection, the less diffuse reflection, so diffuse color is black to compensate for a strong spec. The brighter the diffuse color, the more it will look like an alloy, ie, a mixture of a metal and another material
• Spec: perfect glossy reflection. IOR between 5 and 10. Spec color is tinted the sasm as the metal color.
  

• Add a triplanar map of smudges in the spec to show small variations in reflectivity.
  
• Add a bump that shows small knicks and scratches using a triplanar projection map.
• Add a large wide bump to show larger warble in the metal, see this tutorial: Flat Metallic Surfaces

You might ask, what about the Metallic parameter of the BSDF? Aren't I suppose to use that for metal?

So there are two ways to make your material look like Metal. The first I outline above which uses Diffuse and Spec, the second is using Metallic. So if you take Metallic and set it to 1, under the hood it's actually doing the same thing as the previous material. It's taking diffuse to 0, its increasing IOR to a high value, and then the "Base Color" value becomes your tint color (if you have something like Gold).

There's nothing wrong with using the metallic method, in some ways its simpler because you have to change fewer parameters (and some renderers only have the Metallic option). But I find that the first method is a little more flexible, it gives me more control over the look.

But remember, all of these methods are approximations of the real world, so there isn't a right or  wrong way, just different ways that have advantages and disadvantages. Use either method to achieve the look you want.