Um...movies are usually shot on 35 mm film and go through a lot of processing and editing that takes a long time. That is why they look way better than your video camera. Celluloid film is very high res and infinitely better than video...
...for now. Eventually I expect a digital recording technology to surpass film, but who knows how the hell long that will take.
All those things you mention do impact the quality of your home movies, but the most fundamental issue is the fact that you're recording footage on a video camera.
What kind of camera? In general, a pimpen HD video camera is better than a simple DV camera. I'm sure there are more informed people here who can go into more depth.