Using Natural Light
There are very few applications for on-camera flash in product photography - it’s simply too direct and too harsh. If you use a table or surface placed next to a large window it saves on investing in any lighting equipment, and it also provides a beautifully soft appearance to your products. If you're using sunlight, photograph at the same time of day to achieve consistent lighting.
It’s worth bearing in mind that windows provide different amounts of appropriate illumination, mainly due to their orientation. It’s best to use a north facing window, just like a painter would, for the most diffuse and continual soft light. If you don’t have access to that, you can easily diffuse the light by placing a diffusion material across the window. Suitable materials to use are tracing paper, a voile, or a white bed sheet.
When you’re lighting with window light, there will be a bright side, where the light is striking the product, and a shadow side. This shadow side will typically be too dark, so use a piece of white card or foam board to reflect the light back into the shadows. Foam board makes a great bounce card, because it's rigid and white. Small pieces of white and black card are also handy for blocking or reflecting smaller areas. Pieces of black card can be used to prevent highlights (areas of too much light) within your scene.
It takes a little practise and experimentation to get them in the right place but can make quite a difference to the finished image.
Make sure you turn off any nearby lamps or fluorescent lighting so that you’re using only one light source. This makes it more likely that your camera or phone can select the correct white balance straight away. All cameras and nearly all phones will let you adjust the white balance settings; most likely you’ll have to switch to manual mode. What you want is for white and grey areas to appear correctly. If they’re too cold or too warm the image will look amateurish. If your phone only has white balance presets, the best options to use are a cloudy or sunlight setting.