White balance - The most important thing to do to make the best use of any light available is to white balance. While shooting indoors without a light kit will never produce great results, white balancing will ensure the shot is coloured properly.
Control what you can - If you are shooting in a classroom, try closing some of the blinds and stick to one window. You can soften the light coming in that window using a white sheet.
Judge your light source- If there is only one window in a room, do not position your subject in front of it. This can be done if you have other light sources in front or beside the subject, but it rarely works with one light source. Instead, position the target to have the light beside them, or behind you.
This is an example of what can happen when you put your subject in front of the only light source.
The effect is worse than normal here because of the blue film on the window and the darker complexion of the subject.
Turning him so the window is to the side could have helped, but when a window has a film on it, you may want to consider avoiding it all together.
Stay in the shade - When outside it is usually best to shoot in the shade. Being directly in the sunshine can make light harsh and harder to work with.
Use reflectors or negative reflectors - A reflector is basically a piece of material stretched out over a circular frame. There are multiple colours, but white and black are the basics. With a white reflector you can use it to balance out or soften your light. To balance out your light, you place it opposite your light source. So say your subject is beside a window, you place the reflector on the other side to ensure the light from that window also illuminates the other side of their face. You can also use it to soften the light by placing the reflector between the subject and the light source. A negative or black reflector works the opposite way. You can balance the light by placing it near the lightest side of the subject to pull some of that light away.
We do have one basic three point lighting kit that can produce great lighting for still shots such as interviews. Three point video lighting is all about creating a three-dimensional look. By placing three light sources at strategic points around the subject, each light source illuminates a separate dimension of the subject and creates an image with greater representation of height, width, and depth