Taking pictures of people in a hot tub
Hot tubs are very cool to take pictures of people in, however there are some things you need to know before you go on a shoot. If it is cold out, then steam is going to rise off the hot tub, and if you are using flash or even continuous lighting, actually any lighting from natural on forward you are going to get smears across the entire picture. Steam can make things annoying, so you want to increase the black scale and cut back on the contrast scale when processing them in Light Room (or any photo processing software that has color control across shadows, highlights, whites and blacks). You might also have to boost the color along the way to make sure you are filtering out for the effects of steam in your photo. Steam basically drowns out the subject and makes it difficult to get a good clean picture of the model.
The other thing to think about is the models color when taking the picture. Often we forget that water (blue and aqua) can also have influence on the colors in the eyes. Sometimes you will end up with your model looking like a Fremen from Dune because of over coloring or the natural reflection of the water in the whites of the models eyes. Hands are also important in this one because really all you have is the models expression and the models hands to work with during the shoot. Unless you are going for some of the getting out of the hot tub shots, then you have the torso to work with as well. Posing the model with only half a body can be difficult, so focus on the expression and the hands to convey the meaning you are looking for. Here is my shoot of one model in a hot tub, let me know what you think.