When I was in school I always got nervous thinking about final exams, especially if they were cumulative. The best thing to do is study a little every day; don't cram for it at the last minute. One day we will stand before God and the entirety of our life will be examined by Him. If you want to be ready for that day, take daily Exams and don't wait until the last minute.
Practice examining your day before you go to bed. This discipline has been around a long time and is proven to be very fruitful. Here are a few tips to help you get started.
Set a time, place and time limit. Things that have a place and time tend to move from the realm of good ideas to actual practice. (Example: 10 p.m. Favorite spot on the couch 10 min)
You may want to have a note pad or journal.
When you start examining the day break it into sections. For me it looks like (5-12; 12-5; 5-10). This will keep the whole day from becoming a blur.
For each section work through these 2 words (Grace, Growth).
What happened today in these sections of time that call for you to confess sin and ask for Grace? (Think about your work, thoughts and deeds).
What happened in these sections of time that evidence growth in your Christian Life? Celebrate in gratitude where the Lord helped you to get it right.
I recommend jotting some of these things down. You will see pretty quickly that there is a pattern in your life of when you are strong spiritually and when you are weak.
Next, ask the question, where do I need God's guidance tomorrow? Are there interactions, responsibilities, or situations that you know are coming where you need God's wisdom?
Close your time with prayer, thanking him for today and asking for his guidance tomorrow.
If you can't take the exam every day, then do it Saturday night and divide your week up into 2-3 sections. You will be ready to worship on Sunday. Lastly, you can help children learn this practice early on, and it will keep them connected to the Lord. Don't try to cram for God's final exam, it will not go well.