Before I answer, if there's one thing I've learned, is that Suspension of disbelief works 100,000 times better than the best renderer. Think about that first.
Anyway: I still use firefly for efficiency, and the black body is my trick.
Efficiency: firefly is built into Poser, intimately linked to the scene and the materials room. Therefore every scene I ever save is merely a few clicks away from a nice render. I can save materials easily and reuse them in other scenes. And trust me, with 400 renders per comic, you want to shorten the distance between starting a scene and rendering it... perhaps even at the expense of a little quality that firefly cannot achieve. Remember, life is short... you'll be dead before you know it.
Black body has to do with the behavior of light (no not sexy black men KF ). The idea is this: "A black body (also blackbody) is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence." (Wikipedia: Black Body) In other words this: all materials are defined by the light it reflects, and the light it absorbs, and at which angles. In some circumstances, materials also emit light, but you'll have to do some crazy shit with it like pass electricity through it or something.
But sticking to light hitting a surface, materials either absorb certain wavelengths of light, or reflect them, and depending on their molecular structure, they can differ with the angles they reflect some of the light (a certain color), or all of it (specularity).
With Firefly, you can see 'diffuse' as the color that is not absorbed by the material, or just the base color. With all specularity options at zero, and diffuse values and color at zero, this is a perfect black body. Then when setting colors and values to the diffuse channels, you're allowing the material to reflect that particular light. With specularity, you're emphasizing this behavior under certain angles, and perhaps even allowing all the light to be reflected, in which case you'll get a white patch.
These basic settings originated from the old Poser versions, but with newer Poser versions you got the 'Alt Diffuse' and 'Alt Specularity' channels, where you can attach more specialized forms of material behavior to them, while setting the old basic channels to absolute zero. Subsurface Scatter (SSS) works through these channels, dictating how the material absorbs the light but then reflects it back from deeper within the body and not just the surface.
This is actually a very simplistic approach to Poser's Material room, but when you delve deeper, you'll find just about anything you'd want to try and emulate, limited only by the renderer. The real power of Poser's Material room lies within the ability to apply math functions and more importantly 'masks' through the use of 'blender nodes'. Black and White masks can help to filter out certain material properties to emulate regional effects like non-reflective paint from sweaty skin (like with Sen's skin materials). The Firefly renderer does fine for now, but it can be improved. I'm hoping to see great shit coming from the new Superfly renderer. We'll see.
Now about the actual lighting (and this applies to all renderers): one more tip, and then I'm going to shush (I cannot give away too many secrets), clouds and a cloudy day...! Or better put: STOP FUCKING RENDERING WITH CLOUDY DAY SETTINGS! The reason is that I see a lot of artist just going with whatever settings the renderer provides them, which IMHO is cheating. Its clever of the manufacturer because its the default lighting choice for professional photographers for stuff like... OFFICE CHAIRS! Its mostly just diffuse lighting, or rather like making a photo during a cloudy day. Clouds disperse the light, which is the best lighting for making a photo of an object that needs to be clearly photographed, like a product or something. Its like in a professional photostudio (or like with a porno shoot) there are spotlights everywhere, and it kindof makes all the colors and shadows blend into each other and you get a kindof dreamy palette of shades and colors... which can get rather dull if you do nothing else but.
The reality is that shadows are usually much harsher. Light only comes in through one window, or two, or straight down from the sun. If you have light everywhere, then you're no Anton Corbijn... unless you're trying to emulate a bus or disco interior. Even on a cloudy day in Africa, you'll still get a proper shadow. Its like a lot of 3DCG artists are afraid of shadows, or big dark areas in your images. For fuck's sake look at Rembrandt's paintings, half of them are entirely black, it might as well be painted with tar or bitumen. Shadows define light, you cannot go without shadows. So many 3D renders are FULL of light, or so weakly defined by shadows, which is just false. A lot of artists over-light their scenes thinking that ALL objects in the scene need to be visible. Bullshit. And artificial lights are like 5% of sunlight (probably less), yet I see many artist just blasting some lamp at 100% with the sun at the same strength... NO! And Sometimes artist just blow up their scene with light, casting not a single shadow anywhere, no definition!
Sometimes one light is just fine. Here are examples of scene that were lit with one light:
Do not fear shadows, think of how light behaves, and respect the sun! But remember, without character, a photo-realistic render can be utterly useless.
Edit: read up about photography. In fact buy a book about photography, and you'll learn a lot about renders and Poser, lighting-wise, composition-wise, art-wise... Poser (or DS) is basically virtual photography, the difference being that you get to create the subject
.... and I cannot wait for Superfly!
there is one important thing I forgot to mention and I think this applies to just about any for or art: observation. If you cannot observe, then you don't know what to paint (or render). But sometimes we don't know what we're observing and we need a little help. The whole story above about the black body will not necessarily help you improve your technique, but it will give an extra dimension to your observation of materials. Its like listening to a Symphony of Beethoven, without knowing what instruments are being used in the piece, you'll have only a limited form of appreciation of it, you won't recognize the individual sounds. But if you knew about the individual instruments, like the clarinet, the oboe, the violin section, the timpanis, the brass or the cellos, then you'd have a greater appreciation of their interaction. Likewise with the different properties of light, how colors are mixed, how the shadows are cast, what light is reflected and by how much, and in what direction... if you don't know how light works, how a camera works, or even your very own eyes, your observational skills will be strained.