Lifestyle photography is all about capturing your essence. It is similar to the environmental portrait but it takes it a step further. Wikipedia defines lifestyle photography as "re-creating real life situations in a controlled setting."
Lifestyle photography is very different from the traditional studio portrait session where the subject is posed (chin-up, tilt your head, hands on the lap etc.), photographed and ushered out of the studio. The majority of lifestyle photography shoots take place outdoors or on-location, such as in your home or some other place that is significant to you. Lifestyle sessions usually last from one hour to three hours and include a few formal or posed shots and lots of informal, candid photographs that capture doing what you do best. If it is a family lifestyle photo shoot, be prepared to run after your kids, roll around with them, take them for a piggyback ride or simply enjoy sharing an ice-cream with them - anything that you would normally do on a Sunday afternoon with your children.
In Hawaii, where I live, lifestyle photography sessions often center around the ocean or the great outdoors where people spend a lot of their time. If you are a paddler or a surfer, the photographer will ask you to come to the shoot in your board shorts with your paddle or your favorite surfboard. A typical session will include a few posed shots on your favorite beach and then the fun begins ... its off to the water to do what you love. Some photographers will get in the water with you while others will shoot from the shore.
This is not to say that lifestyle photography can't take place in a studio - it can, but a studio can be limiting. There are photographers who specialize in studio lifestyle photography, and if the outdoors is not for you, this is a good alternative.
Preparing for a lifestyle photography session is easy after you find the right photographer. Wear what you normally wear to do what you love, then show up for the session with a good attitude!