Two of best methods:

1. Write lightly with hard pencil information u need on sheet of paper which u will use in test. Text is invisible from medium and longer distance.

2. This is second method, more complicated. So i made a drawing.

http://i35.tinypic.com/2d0yvsz.jpg

/\ very usefull

Time for conclusion.
I know a lot of cheating methods but i use it hardly hardly ever i do not even remember when i was last using one of those.