Incomplete After-Blessings (Bracha Achrona)

You must repeat the after-blessing for mezonot, wine/grape juice, or any of the Five Special Fruits if you ate items from more than one of those categories, said the after-blessing for just one of them, and forgot the other. 
Example
Situation You ate mezonot and some figs, said al ha'michya, and forgot to add the words for al ha'eitz.
What To Do You must say the after-blessing al ha'eitz.