Making your calling and election made sure is a promise that God reminded the Prophet Joseph in D&C 3 - 5. He reminds him during his chastisement of the Prophet and in section 5. 

 Here is what I cover:
#1 What is the doctrine of making your calling and election made sure? 
#2 Who is this assurance afforded to?
#3 How can one achieve it?
#4 When can one achieve it?
#5 Why is it something we should strive for