I've been getting back into video, and the first thing you learn is the importance of lighting - a camera that gives beautiful quality outside will often film dark, grainy video inside, even with all your normal lights on.
To solve this problem you need dedicated lights, two or even three points of it extra depending on the existing lights in the location. The problem is that lights for video and photography are expensive and only sold by specialists. Ordinary floor standing lights can be bright enough, but having all your light come from something as small as a bulb causes "hot spots", uneven lighting where the middle is much brighter than the edges, causing white shiny spots on noses and foreheads.
What we need is a lamp that reflects all of the bulb's light to the target and diffuses it, that is, smooths it out and softens it for even lighting and a natural look. And we need to do it without going skint.
A $200 tripod mounted softbox, with and without diffusion filter.
The principle is a lot like a torch or a bike headlight, a shiny reflector sends the light forward to the target. Only instead of a lens for a focused beam, we're using a diffusion filter.
The reflector box is made of cardboard panels with kitchen tinfoil glued on, and then taped together at the edges. It's then reinforced at the front by the reflector frame. I recommend corrugated brown type that big boxes are made of.
After comes the Velcro. This lets us easily take the diffusion frame off so that we can change the bulb eaily. Inside the diffusion frame are two sheets of 42x38cm white grease proof paper, the kind that you use to cook food in the oven.
The Lamp itself is an ordinary light fitting like you might have hanging from your ceiling. The reflector box attaches the same as a lampshade does. I would strongly recommend using CFL or LED bulbs to prevent heat buildup in the enclosed space.
Below are some diagrams that will build one for two lightbulbs, based around the 42x38cm baking paper I found in the kitchen. I haven't bothered to create printable templates because every part of is box is bigger than an A4 sheet anyway.
You will need to figure out your own mounting solution. I suggest building a wedge shaped section under the bottom of the reflector, then epoxying on a 1/4" nut. This will let you screw it onto a tripod.
Depending on what size cardboard pieces you have, you might not be able to make the frames as one whole piece. here are two diagrams for making them out of smaller parts. A and B are to be glued one on top of the other for strength.
Here's the reflector. I went with two bulb fittings here with the idea of using two ordinary 60W-equivalent CFLs, because most people have a few of lying around in cupboards anyway. It also lets us fit two switches - turn one on for low brightness, or use both if you need it. There's no such thing as too much light!
It's all just taped together at the edges. Parcel tape or wide cellotape is best. If you're into professionalism at all you can paint the outside black.