It’s going to be impossible for you to replicate the special environment that an analyst would have in their studio, so you’ll just have to do the best you can.
The first issue is lighting and location. Some like to take them outside on a cloudy day, so if the weather happens to cooperate, that’s great. Also, like in all photography situations, you want the light source in front of you. My cloudy-day alternative is to stand in front of a window with the blinds down in the afternoon. 3pm is usually a good time. You don’t want the sun to have begun setting, but you don’t want it to be super sunny, either.
The next important thing is to lock your white balance. Use a white piece of paper to get the white balance setting right. Focus the camera on a white piece of paper and adjust the camera until the color of the paper looks as close as possible as it does in real life and lock it. DO NOT take pictures with the white paper by your face. If you’re using a phone camera, download an app like Camera+, which allows you to set the white balance manually and lock it. You can either choose from a preset setting or adjust it manually. It’s important for all of the photos in a single session to have same lighting and white balance in order to make a fair comparison.
Then start taking pictures. It’s nice to keep draping photos for reference. Many like to post their photos in places like “Figure My Season” on Facebook, but again, knowing which feedback to take into consideration and which to ignore is difficult. People work with different systems and have varying levels of knowledge. Some would dismiss Dark Autumn for me based on my hair and eye color, for instance, since in their system, Dark Autumns all have dark hair and eyes and absolutely have to wear a heavy makeup look. And again, as I mentioned, sometimes people just react more positively to the seasons they like, or they don’t know what effects to look for on the face.
The last major issue with photographs is that they’re just not going to be as accurate as how you look in real life. So don’t rely on photographs alone.