One of the best ways to take people's photos is to shoot them when one least expects it!
For example, when you see 2 persons talking, what you should do is to just aim your camera at them without asking their permission and quickly press the shutter button! Likely, they would just give you a weird kind of stare afterwards which is apparent if you use a Colorsplash Flash, but if you’re successful, you will be rewarded with superb portraits!
You will effortlessly capture those unguarded smiles, silly faces and their natural selves. The point is that while they are not expecting to be photographed, you can deliberately avoid those unnecessary pretensions, because they don’t have the time to look beautiful, cool or whatever. Instead, they’ll simply look as what they are, absolutely relaxed, and sometimes very funny in your photos! ;-)
I totally recommend using the Lomo LC-A+ for this one. No shutter lag, easy to operate and it’s fast enough to take those perfect candid shots!