What do you usually do the day before an exam?
Before the exam, I make an outline, I listen well in class and I practice exercises.
Before the an exam, I make a outline, I listened well in class and I practised exercises.
the exam - a specific exam
an exam - any exam that you may take
Before the exam, I made an outline, I listened well in class and I practised exercises.
Very good but it's already happened so 'made' which is the past tense of make, 'outline' begins with a vowel so 'a' becomes 'an'.
If it was a plan for future exams then 'make' could be used but 'listen' and 'practise' would also have to be in the same (present) tense.
Before the exam, I make an outline, I listen very well in class and I practise the exercises.
Por favor, solo usa o presente ou pasado, nao ambos juntos.
Bom sorte e aproveita o ingles bem!