CHANGING GEARS TO ARNOLD
Arnold is pretty cool. Its has a very simplied shader system and its easier to create the materials you want. Forget what you know about Mental Ray. Mental Ray is finally dead and it should stay that way. You also can forget about lambert, phong, blinn as well. You only need to care about these materials:
aiStandard can be used to create most of the materials you need. ie glass, frosted glass, liquid, crystal,
aiAmbientOcclusion is great for really fast ao renders. It also ignores light to make your renders very quick and still looking good.
The most important aspect when it comes to adjusting your material properties so to create a world to evaluate your material. Lighting is perhaps the most important aspect to making a material look the way you want. There are a couple ways to light your environment in Arnold.