Prerequisite concepts
Difference / Change
The derivative relates how much $f$ changes as $x$ changes
The derivative is a ratio of small changes
The derivative can be approximated by the slope of a secant line
The derivative is a limit
The derivative is a function
The derivative of a constant is zero
The derivative is a linear operator
Power law
The derivative at a cusp is undefined
Variables can be held constant
Product rule
Single variable chain rule
You can flip a derivative
"With respect to what" matters
The magnitude of the derivative at a point is the slope of a tangent line at that point
Understanding both difference (how far apart two values are at one time) and change (how far apart the value of a single parameter is at two different times) is necessary for understanding derivatives.
The derivative of a constant is zero
The derivative of a constant is always zero. This can be understood by thinking of 'The derivative is a ratio of small changes,' as the amount by which a constant changes is zero.