Most people will never get close to opening the box, because they won't realise that a shake is needed to start the ball rolling. So even the simplest maze will work fine, and make it easy for you to remember: 167 or the more labyrinthine 175.
But if you want to make it even harder, you can start to incorporate choices and dead ends (a real maze). This makes it much harder to solve the maze by luck but also makes it harder for you to learn. Here are some good examples: 170 has just a couple of dead ends, while the more fiendish 254 has 6.
We need a continuous path from the start (circle) to the end (cross). Otherwise the ball can't drop into the hole and release the button mechanism.
An unconnected block is like an island. We have to keep all the blocks connected to the edges because otherwise they'll get lost when we cut the maze out with the laser cutter.