Why worry about the small things, they aren't worth much and waste time. There is an Ethiopian proverb that talks about the power of small things: "When the spiderwebs unite, they can tie up a lion."
In the Bathroom
Shampoo - I was watching a shampoo commercial on TV and found it interesting that the person in the commercial had used enough shampoo that they could spike their hair into the shape of a Mohawk. That meant that they had used more than the recommended quarter size amount, or in his case, since it was shorter, nickel or dime shaped amount.
The shampoo bottle doesn't have a recommended amount to use on the bottle, they just hope you will think of their highly suds out commercial and use enough to make your own Mohawk.
Toothpaste - Toothpaste commercials again show us the way not to use toothpaste. That large amount of toothpaste looks really pretty on the brush, but is a waste. (If it all even makes it into your mouth and not onto the sink.) The dental association says, "Simply squeeze on a pea-sized dab of paste on the top half of your brush....the paste should foam enough to cover all of your teeth."
Toilet Paper - This subject can get kind of stinky with some people, such as when Sheryl Crow suggested we only use one square or even before that, Elaine from Seinfeld begged the person in the next stall to "spare a square".
Water - It runs throughout the house, but doesn't have to run down the drain. There are 25 ways you save water and I have one way to save hot water in the shower, not including a low-flow shower head.
In the Laundry Room
Laundry Detergent - They give you a measured cup for the load size you are using, but do you have to use that amount? Based on responses over at the Dollar Strether, they say to agree on ¼ to ½ of what the suggested amount is.
Hot Water - Using cold water cleans just as thoroughly as hot water and keeps your clothes in continued good shape and retain their color. Plus you don't have to wait for it to heat up. Then save the hot water to wash towels/linens and underwear to kill bacteria.
In the Kitchen
Boiling water - Just enough water to cover the food and a cover over the pan saves on heating water.
For dishwasher detergent they have packets that can be used and if you compare that against the size of your compartment, you don't have to fill the compartment up - about 1-2 tablespoons.
Electricity - Using less electricity can be viewed the same as using a car to run errands, bundle it in one trip. That saves you the time to heat up for each item you want to cook each day. An already warm oven can allow you to move the food in and out faster, saving time.
This idea can be used for the dryer as well. An already warm dryer allows the 2nd batch of clothes to dry quicker because the dryer is not having to ramp up to the warmth needed.