Did you focus these on manual? I've tended to spot meter everything, along with the focus, and haven't experimented enough with the different metering settings on the camera.
I seem to be able to improve one aspect of technique at a time, then I look back later on and realise that I'd ruined a shot because I hadn't exposed it correctly or thought about increasing the aperture or changing the ISO... Ad astra per aspera
Spot metering is not what I would have chosen for a shot like that. What did you meter off? Or do you mean the matrix metering?
Any useful summary for me to bear in mind on metering? Ad astra per aspera
Matrix metering isn't good when its voodoo guesses wrong - back-lighting is a classic, though with D-lenses (that tell it where they're focused) it can do some magic. Lots of light or dark areas in the frame can confuse it too. Snow, sand, etc.
One recent example that occurs to me is shooting a small stained glass window from inside the church.
The camera decided it was really dark because the window only took up a relatvely small amount of the frame, while I really wanted to expose for the light outside the window, which made the interior stone black but showed the colours of the window nicely. In that case I spot metered on the window.
when its voodoo guesses wrong
Exactly... :-) "What can I do, What can I write, Against the fall of Night". A.E. Housman
I manual focused because it was a 50mm Nikkor-S that is about thirty years old :-) The second shot was with AF (20/2.8 AFD).
The first picture isn't really sharp (and the subject was speaking so his chin is more blurred then the rest), but acceptable in small sizes, while the second picture can be blown up at decent sizes !
On the D200, matrix metering is quite good for most cases (apart when you have a direct light in the frame), because I started shooting a long time ago I'm more familiar with centered average metering, as I know what I will get. I usually keep spot metering for peculiar cases, as in the second picture with the big white diffusing background...
Don't worry about improving one aspect at a time, it'll soak in :-) Apart from very specific shoots (macro, astronomy, stills, etc.) you shouldn't have to "think" too much, meaning the basics (composition, settings, etc.) should be more on the instinctive side... But to get there, most of us ruined kilometres of good film :-) "What can I do, What can I write, Against the fall of Night". A.E. Housman