It is a good thing for students to self-check their work.
The results of some calculations can be checked easily. For example, the solutions to an equation can be substituted back into the original to see if they really work, and integrals can be differentiated to see if it comes to the original function.
In having trouble coming up with effective ways to self-check derivatives.
I am not looking for general advice like "look for minus-sign errors", but methods that will indicate that a mistake has occurred somewhere. Note also I am not talking about differentiation by first principles using limits, but using the rules of differentiation (powers, product rule etc). I would also prefer at least some things that don't require the use of a graphics calculator/computer algebra system.