I may be wrong but most of the population spends a great deal of time bathing. I know I'm no stranger to spending hours basking in warm water, #BathsAreLife, but let's face a harsh reality, we do a lot of stuff in the shower that does not require the water running. While some people might not feel clean enough being under the water for a short amount of time, it might just be the chemical bases in your soap or shampoo that are clogging up your pores.
Try shutting off the shower for a minute or two while you let your hair conditioner sink in. Brush your teeth during the water off time and rinse when you wash your whole body.
As part of a promotion for water conservation in Saskatchewan I was given a small sand hour glass (looks like an egg timer) for my shower that times out at four minutes. It is stipulated as enough time to have your pores open up from warmth and steam, wash your hair and step out. If you take a long time in the shower stop the water for intervals that you are not actively using the water. You'll be amazed at how your water bill shrinks.
For those with a green thumb that find themselves wishing for a rain barrel to keep up their watering schedule without the water bill, invest in a large basin that is manageable to stand in and then tote around. Use products that are safe for the environment so your plants don't get a shock and die on you.
So lets say you're about to start your shower. You don't have a timer. What do you do??
Close your drain. Use the water level to gauge how much you have used. Stop before the water makes it to your ankle. When you get into the habit you'll figure out for yourself exactly where on your foot is your four minute mark. You'll probably eventually be done before you even get to it.
Couples are lucky to be able to halve their water bill right away by having an instant shower buddy. Be sure to work on developing communication so one of you isn't always freezing and never wanting to experience it again. Kind of hard to save water/money if someone resents the experience.
Baths are a bit tricky. Begin by sitting in the tub as it fills up. Your body will displace the water and fill up the tub with just enough to your desired level. No more water splashing out as you get in. There isn't really any way to avoid being wasteful except to limit the number of them that you have.
If you have control over the temperature of your water heater you can turn down the maximum temperature. A few degrees (or a lot) need to be tested over a few days to allow temperatures to drop. By having a lower temperature you will be using less energy to warm the ever ready tank. Setting a lower maximum temperature will also help to prevent scalding yourself in the future.
Good luck and have fun, be it for the better conservation of the planet's resources we use or your pocket book.
PS If you don't have low flush toilets then open up the lid on your tank. Grab a brick or a sand filled one liter plastic jug (trust me when I say that a water filled one will not be heavy enough to stand up against moving water), and put it in any open area in the tank. This will disperse the water and you will save with every flush.