Rookie, I'm consider myself new to photograph and I'm always learning but I will try to answer some of your questions.
I think the Golden Rule is, there are no rules, just guidelines yet they get called rules anyway.
For example the rule of thirds - while its commonly used, it doesn't mean all images have to abide by these "guide lines" breaking them when needed is a good idea otherwise it will hamper your creativity (some thing just look better in the middle, etc etc).
You've already got a good handle of another um, lets say guideline, which is experiement and try new things, sometimes they will work, something they don't, it all helps you grow as a photographer.
Exposures look decent in these shots and the D70 can handle most situations alright on Matrix Metering which lets you concentrate on composition a little more until you comfortable with both at once. (I'd suggest you could try a similar strategy as I did, and learn the different facets in steps, not try to fiddle with them all at once). For example, one outing concentrate on framing the shots, another concentrate on exposure, another maybe concentrate of getting sharp shots, or good use of DOF. The good news is the more you play around the more you pick up.
I feel like I'm rambling on a lot right now, so I might draw this post to a close and say that, you are definitely in one of the best, if not the best learning environments here on the forum. Many members are willing to offer their experience, opinions and expertise, or just answer simple and complex questions you may have, you just have to ask, and sometime be a little patience for the answers
