Here are some tips i find helpful. 
What frame rate are you using? I think frame rate is an important factor of professionalism.
Lighting: Use three lamps. One key light, one fill light and a backlight to light from behind.
If your capture program has frame averaging, try that. It removes most of the grain.
Ease in and out: In real life, things don't move at a constant rate. It accelerates in an out, like a car.
Rotoscoping: If your capture software has that feature, you can import a video clip as a reference video. If not, you can use Quicktime or something like that and step through the video frame by frame.
Angles: Never use the same angle too long. That's boring.
Camera movement: That can improve everything a lot. Tracking and pans are examples of this.
Set building: Don't use one wall. For the walls, don't mix up colors.
Watch other videos to get inspiration.
Hope this helps 