1. Keep a stick of butter at room temperature in a closed container. It doesn't seem to go bad (at least not if you use it within a couple of months) and it's so much more spreadable.
2. Use the broiler in your oven. It makes food taste similar to if you'd grilled it. (This might not be a "hack," since it's just working as intended.)
3. Make buttered (or olive oiled) toast in the broiler. Put on the butter in advance, then broil until it's golden brown. That way the fat soaks through.
4. Clean your blender by blending water and detergent.
5. Make bland coffee taste better by adding cinnamon to the grounds before you brew it.
6. Use your stale bread for making french toast instead of throwing it out. This is how french toast was invented, I think, but it might not be obvious that you can do this.