1. To understand the aims of piloting and to apply this knowledge to potential research

2. What is a Pilot Study? Small, trial versions of proposed studies.
Any part of the study could be tested
The validity of the measure (e.g. does the questionnaire measure what it is supposed to?)
The effectiveness of a procedure (e.g. does it take too long, are the instructions too complicated, have any steps been left out).
The pilot study is an important part of the experimental process and should be used where possible.

3. Purpose of Pilots
To test the effectiveness of a study and make improvements
They are helpful in identifying potential issues early, which can then be rectified before committing to the length and expense of a full investigation.

4. Writing about Piloting in exams
Make sure answers are specific to the context.  
For example, if the question referred to an experiment investigating the effects of a strategy to improve memory, you could refer to the need to check the stimuli being used in the memory test and how long participants should be given to learn them.