Candid photography is one of the best ways to capture people in an environment that they feel comfortable in and these photos are generally the ones that will rehash old memories when looked back upon. There are a few mistakes though that could kill the image, this tutorial will help point out what not to do.
Don't forget your camera at home. Candid shots in-the-moment, you never know when that moment will happen, so always be prepared!
Turn the flash off! You may be able to get away with the first shot but each and every one after that people will be aware you're around. The flash isn't so bad if you're looking to capture candid shots during a wedding reception, but if your goal is candid street portraits you don't want anyone to know you're shooting.
The subject isn't always the main focus of a candid shot. Don't be afraid to zoom in and crop some of the forehead off or shoot at an odd angle. Take into consideration how the person is currently in the environment and try to either include that into the composition or completely isolate it.
Get down on one knee. The perspective from three feet is significantly different from your standing eye level and provides more intimate photos.
Blend in, don't stand out. The key to candid photography is to capture people in un-posed, natural situations, laughing, crying, enjoying moments of their lives. If you're dressed in loud colors or in the middle of a conversation you could be missing out on something fun or important happening.
Have patience. If you're in a rush or impatient for a shot you could miss out on the best situation to take photos. Candid photography isn't staged, it's the exact opposite, therefor you must flow and work within the scenario you are created and not try to dictate what happens.
Don't ever ask someone to re-do a pose, laugh, hug or other gesture because you missed it. If you missed the shot, take a breath and relax, another will happen, but don't force people to re-do anything.
Don't miss the story. Photography is commonly called painting with light but it's also all about telling a story. Before you even put the camera up to your face take a few moments to evaluate the entire area you're shooting in or walking through. See what the flow of people is, determine if you should be stationary in one spot capturing people passing by or if you should actively mingle within a crowd. Look for moments between two or more people and how they interact and frame your shot to capture this engagement between the subjects.
Forget about being selective when shooting. Digital photography means the cost per shot is near non existent, unlike film where every frame on every roll cost money. Because the difference between a great candid and a miserable one could be only seconds apart, over-shoot candids and weed them out in post-production. Better to have several similar shots to choose from instead of one almost great shot.
Candid photography is very much like photojournalism, capturing moments of time that are happening, telling your story through still images. Many shooters struggle with candids at first because of the inability to not control the situation. Look at shooting candid subjects like the wind, you can't control it, you can only capture what it does, where it does it and with your own vision and angle.