I only ask because the CofE has published some new prayers to help people through exams. However everyone I know who has exams has already started them, and some (KS2 SATS) have already finished. So whether God can apply your prayers in retrospect to make you do better in your exams than you actually managed..... no my brain is starting to hurt.
The 'prayer' page on the CofE site also has prayers for Burma, China, financial management, and various general prayers for the world. If you're stuck for some materials, and someone hasn't returned your copy of John Pritchards Intercessions Handbook, then it's a useful resource. There's a more general story about the site and how well it's been used here.
Here's one of the prayers:
Prayer suitable for use by teachers
I don't suppose that you have time for this, Lord, but I am nervous. Not for myself, but for my class. Today they have that test, Lord; the one that seems to determine their future.
They have worked hard, so have I!
They deserve to do well.
It should not be a problem, but... well, you know this lot, Lord.
They can get so silly if they are nervous or excited.
They forget things that normally they know, like their names and the date! O Lord, they are in there, and there is nothing I can do but worry.
Keep them calm, Lord.
Keep them focused.
Let them do their best.
At this moment they really need your help.
which is good in that it models a more conversational style of prayer, but not so good in that, if I'm having a conversation with God in this kind of style, it seems really strange to use someone elses words. Maybe it works as a reflection to kick off our own prayers, or to put into words what someone is feeling.