Okay please forgive me if any of these were already listed, i tend to speed read, and by speed, I mean gloss:
Skip the shower every other day. A slash of water will freshen you well enough.
Shower and blow dry at the gym.
Floss. Floss obsessively. It will save TONS of dental bills.
Save the water you run while waiting for the faucet to get hot. Use that water to water plants, feed the animals, or water the garden. (Consider having a large plastic garbage can near the kitchen to hold it all).
Piggyback your driving trips. And keep your trunk as empty as you can - extra weight burns fuel.
Don't flush until you "have" to.
Use a calendar system to make sure your bills get paid on time. I take advantage of the 0% balance transfers on credit cards, make the minimum payments for the duration, invest the rest, and then pay the balance a week or 2 before the date the agreement expires. The risk is that you will pay late and trigger a voiding of the 0% offer, but if you're attentive, you can make some $$. (Right now I am minimally paying down a $29,000 balance, and earning about 5% on the funds). This gambit is NOT for everyone, I know.
Get your Swagbucks groove on. I get about $5 to $10 in Amazon credits every month. It's really painless.
Grow something green that you normally buy a lot of. I have romaine lettuce growing nearly 9 months out of the year. That can save me $100 or more a year. Growing broccoli also saves me another $100 a year. Give extras to loved ones, and you are saving them money. I also raise chickens and my free range (nearly) organic eggs run me about $2.25 a dozen. If I sell some, that's icing. But they are mostly consumed and shared with family or bartered.
Area rugs keep your wood floors a little warmer than no rugs.
Buy kids clothes at thrift stores. Many are in excellent condition and the kids don't care if they are used.
Subscribe to freecycle and check the craigslist "free" items. I got 75% of my toddler gifts from freecycle and craigslist. Plus, you are buying local (if you pay) and re-using, which is all good.
Make a list of the "things" you need to buy that you can put off and piggyback. Lists are very good for disorganized and forgetful people who then end up paying more than necessary because they didn't "think about it" when they were at the dollar store or the garage sale.
Keep your coupons in your car, not in the kitchen drawer. That way you always have them when you are at the store.
Watch your cable bill. Cable companies are notorious crooks. Periodically make sure you have the "best" bundle. They won't volunteer that to you as time passes and you have a crappy bundle.
Don't run to the doctor will nilly for every little thing just because you have no co-pay. It could bite you in the butt (this is directed more toward younger readers, or anyone who might have to be rated for an individual policy). Especially try to avoid having any record of mental illness items such as counseling for stress, anxiety, depression, alcoholism, etc. I know those are serious burdens, but I think it's worth mentioning if you can manage to find a more private manner of coping. Insurance companies are crooks and will use all your facts against you! (Awful lot of crooks in America, hmmmm!)
I have many more, having spent 49 years of seeking new ways to save. but I don't want to hog the page!