Bontoc (Philippines) 
(data from Robbins Burling, Patterns of Language)

fikas  'strong'       fumikas  'he is becoming strong'
kilad  'red'          kumilad  'he is becoming red'
bato   'stone'        bumato   'he is becoming stone'
fusul  'enemy'        fumusul  'he is becoming an enemy'

List all the morphemes in the data, with their meaning or
function.

ANSWER:  The data consist of adjectives or and related verbs. 
You can see right away that the verb meaning 'he is becoming X'
is similar to the adjective or noun meaning 'X'; what you need to
do is explain how they are related.
     So, take your first pair, and notice what is the same and
what is different about them:

          fikas
          fumikas

So your initial hypothesis is that there is a morpheme -um-
which derives verbs from adjectives.  Notice that this morpheme seems
to be stuck in the middle of another morpheme, rather than before or
after it.  This kind of affix is called an infix.  Don't worry
if you come up with an answer that seems weird--languages do things that
you would never imagine.  If you do the analysis right, you'll get the
right answer--trust your analysis, not your intuitions about what a
likely answer might be.
     Now, test this hypothesis against the next pair:

          kilad
          kumilad

Still looks good; now check the nouns:

          bato
          bumato

          fusul
          fumusul

So the hypothesis works for all the available data.  Then your
answer is:

fikas  'strong'
kilad  'red'
bato   'stone'
fusul  'enemy'
-um-   derives verbs from nouns or adjectives

A little historical note--the word Bontoc, the name of an ethnic 
group and language in the Philippines, is the origin of the American 
English word boondocks (as in out in the boondocks).  The 
expression dates from the Philippine War.  (In case  you never got to that 
in U.S. history, the U.S. took control of  the Philippines from Spain in the 
Spanish-American War, and then spent several years viciously suppressing a 
Philippines independence movement).