Do not be concerned about being a brilliant student. That phrase can have many different meaning. Your concern should be to do the very best that you can.

Some suggestions are:

Attend all classes on time.

Always be prompt.

Pay attention in class.

Take notes and with permission record the class lectures and discussions.

Review all work on a weekly or biweekly basis.

Participate in class.

Ask questions.

Read a great deal.

Have friends on your level or above

Do extra work.

There are techniques about how to study and to score well on tests. Learn them.

Accept criticism.

Good luck and enjoy yourself too.