If you really want to improve, go watch a few model videos from these people:
Scott, He got a lot of viewers for a reason. Examine how he talks to the camera, and how he explains things.
Scale model mad man: He doesn't have a lot of videos, but what he does have up is quality
Dreamknight: Look at how he interacts with the camera. It is like he is talking to a friend.
terrainoob‬â€: Again he is talking to the camera like it is his friend, especially in the earlier videos
And last of all:
hobbylink‬†: They are very professional with their videos. I think that they have a camera man to take them.
The next few things you should do is get a tripod. That camera is not heavy so you don't need an expensive one. You can find a good one for under $30. I have three of them, one was cheap, but it works great for a light weight camera. Since you are taking video, try to find one with handles on it, instead of knobs. Kind of like this one:
http://www.amazon.com/Digital-Concepts-TR-60N-Camera-Carrying/dp/B000093UDQ/ref=sr_1_3?s=photo&ie=UTF8&qid=1298353375&sr=1-3
It will make it easier to work with for adjusting your cameras position. Knobs are more for still images.
Second, good video editing software. You don't have to spend a lot here. The software I use cost me $60 on Amazon.com. This is the software I am using and it is on sale for $30, with free shipping:
http://www.amazon.com/Corel-VSPRX3ENMB-VideoStudio-Pro-X3/dp/B002J9PO2E/ref=sr_1_6?s=software&ie=UTF8&qid=1298353446&sr=1-6
And last of all, good lighting helps. This is one thing I need to fix with my videos.