I usually have notes hidden around the stage, but the audience never knows that I'm looking at them.
I look at my notes that are lying flat on my table when
1. The audience is laughing
2. When I'm pushing buttons on my laptop
3. When I walk past the table looking down and holding my chin as if I'm thinking.
4. When I go to the table to pick up a prop or piece of paper.
5. When the audience is watching short videos on the screen.
Some people tape their notes to the floor when they are on a raised stage, but I don't like that because you have to look down too often for no apparent reason.
Another good trick is to lightly pencil in notes to yourself on the edge of flip chart pages. The audience can't see them, but you can when you are near the flip chart.