First, your translation is nearly good and would have been understood in actual state.

• A better sentence would be

  Tu dois bien étudier cette fiche avant l’examen.

• “étudier” could be used in a work context, not only in a school one. (But not the word “exam”)

Now if you want to have a more common word and if it is for a spoken usage, I recommend to use travailler :

Tu dois bien travailler cette fiche avant l’examen.

You can use the generic term of “document” in “fiche” replacement :

Tu dois bien travailler ce document avant l’examen.

You can be even more chatty by using the familiar verb “bosser” instead of “travailler” and “exam” instead of “examen” :

Tu dois bien bosser ce document avant l’exam’.

And to emphase it, you could also turn into a question :

As-tu bien bossé ton document avant l’examen?

“étudier” is a good translation for “to study”. It can apply to any kind of studying: school, university, professional case study… Some other words can fit here too, even if “étudier” is fine:

• travailler (as in “travailler son texte”, what does an actor when repeating). Here it changes a bit the meaning, suggesting you are both re-writing the sheet and reading it several times to learn its content.

• réviser (as in “réviser une leçon”). It means you already know the content of the sheet but you need to know it better. Usually you “révises” only the content of a lesson, not the support, so it would be strange to say “réviser cette fiche”, but it could be heard.

However there are some other mistakes in your translation:

• “Should” corresponds to a conditional mode in French, and “you should XXX” is usually translated with “tu devrais XXX”

• “bien” is usually placed before the verb. It’s only placed after the verb in some specific cases.

• “carefully” can be translated with “bien” but you are weakening a bit of the meaning. A better translation could be:

Tu devrais étudier attentivement cette fiche avant l’examen.