This is a very open topic
so first pick a day of your choice.....like any festival day, your first day in school, the day you met your best friend and so on...
then start by describing your emotions
how happy, nervous or excited you were
then say how you spent that day
and finally how the day ended
if you pick an incident that happened in you real life, it will be easy for u to elaborate.
finally if u pick a happy day, say that u wish for another day like that in your life.