If you think you might ever take a photo of a person, this post is for you. I'll show you the simplest way to make your subject happy--soft light.
I took this image a few months ago when I was experimenting with hard light. I stood in my dark bathroom and shined a flashlight up from the bottom of my face. This was the result.
It's high-contrast, raw, and intense. You can see every wrinkle, freckle, and imperfection--useful of that's what you're going for, but rarely how anyone wants to be depicted.
I took the second photo in very soft light. I stood in front of a south-facing window during the afternoon, with the light diffused through white, sheer Silhouette window blinds. See any difference?
The soft light is a lot more forgiving and flattering. While I am wearing some makeup in the second photo, it gets little credit for the limited wrinkles and imperfections. I also did not edit the image to remove blemishes and wrinkles. It's all about the light.
I'd much rather people think I look like I appear in the latter photo, although both are me unedited. On an average day in the real world, I probably fall somewhere between the two photos--neither as haggard as I appear in the first nor as young as I appear in the second. Neither is a trick of editing; the light makes the difference.
To understand the difference between hard and soft light, picture a lamp with a bare bulb. The bulb casts a hard, bright light and harsh shadows. If that lamp has a shade, however, the light is filtered through the shade and reflected across a wider area. The shade effectively increases the size of the light source, creating softer light and producing softer shadows.
If you want to photograph your friends and keep them as friends, avoid hard light from a small, single source. Naked light bulbs and direct mid-day sunlight are particularly unpleasant.
Try instead for soft light, which falls on the subject from multiple sources or is diffused or reflected. Use early morning or late afternoon sun. Place your subject in the shade or wait for a cloudy moment. If you are indoors, use sunlight bounced or reflected off the wall, ceiling, or floor or a piece of craft store white foam board. If you are using a bulb as your light source, diffuse the light through a semi-transparent white paper or fabric, like a sheet.
Studio photographers have all kinds of tools to create soft light, but the average amateur photographer can get the same effect by choosing a good location and working with things they likely have around the house. From now on, all photos of me will be taken in front of my living room window, in the afternoon, with the blinds drawn.