So let me give you some general rules I use for all of my senior shoots.
Keep in mind there are two types of senior shots, the image they will use for their yearbook, and the image that the parents will hang on the wall of their house, the latter being a much more "staged" artistic photograph.
So the details I am about to share are for the those that are intended for the yearbook.
1. I have never had a senior as happy with indoor shots as they are with those taken outdoors, so I will always start shooting outside and it's not that uncommon that we never make it inside.
2. When scheduling I look at my appointment book first and then at the forecast second, if it's going to be a sunny day I schedule the shoot during "the golden hour", if it is an overcast day I select the first available slot.
3. During the session I shoot with two bodies, one has a 28-70 lens, the other has a 70-200, this way I'm not swapping out lenses (making it a quicker shoot). If I don't have to change lenses while shooting outdoors, especially when at the beach, I am a very happy guy.
4. This is the part that is going to give some camera snobs heartburn, but before I start shooting the client I will quickly grab a couple sample images using different settings (checking exposures) and quite often end up shooting in "P". For the most part my camera does a great job metering and adjusting for an outstanding outdoor image (I shoot with a Nikon D300 and a D3). I want to be absolutely clear that this only applies to shooting outdoors, I never shoot on "P" indoors!
Here is a good example of an image shot during the "golden hour" and how nice it makes the skin look:
These two images are examples of why I use two bodies/lenses.
This image was shot with a 28-70, notice the railings in the background.
The image below was shot with a 70-200, the background is much more blurred giving the image a more "abstract" background.