A few of mine:

If you ride an MTB, get slicks if you ride strictly on the road, such as during the commute hour. You'd be surprised as to how much faster and easier you ride.

Use a credit card or a business card to help you set the toe-in for your brake pads. Please the card on the rear 1/3 of the pad and tighten it. This will toe the pad in approximately 1 degree, helping you get rid of your squeaky brakes.

Oil your clipless pedals every time you oil your chain to help your shoes to easily click in and prevent squeaking. A teflon-based lubricant is good for me.

If your water supply is low on a long, hot ride, breathe through your nose and not through your mouth. This will help you maintain your body moisture and save you from having to drink all the time.