Photograph the person with a portrait lens and with minimum depth of field, unless of course, you’re doing an environmental portrait. Make your subject feel comfortable and relaxed by talking to them and telling them what you would like to do. If it’s a formal portrait in the studio, make sure your lights are all set up. Your camera should be set to the right exposure beforehand, as well as knowing where you stool will be placed if you are using one etc. Have the person sit with one shoulder a little more towards you instead of straight on as it’s much more flattering. When you are making these portraits keep shooting and show the person a photo or two so they become more involved in the process. Always suggest to the person that they wear something they feel comfortable in. Layers of clothing are nice for both men and women as it adds interest. I personally like soft feminine and flattering necklines as well for women. If they wear glasses either ask them to remove them or place the glasses a little lower on the bridge of their nose so as not to see the reflection of the lights (you might have to move your lights.) Remember most women need softer lighting as it’s more flattering. When photographing in available light and on-the-fly you need to quickly come up with an interesting and appropriate background which will not detract from the person. Obviously if it’s an environmental portrait you may want to use the person’s workspace or living space to tell something about the person. If you can, try to have more than one idea where to place the person and move them around. Again more times than not, this relaxes the person and puts them more at ease, knowing you know what you’re doing.