Put down a base of making tape...
Wow, there is no way to make masking tape on a beige wall look interesting...
Then create a loop of masking tape, but with a tail
- stick the tail to the base of tape you put on the wall
Put tape loops on the corners of your poster like normal and stick it to the wall with the hanging loop in the center of the poster -
I don't know the precise physics of how this method works, but the hanging tape loop must distribute the weight of the poster, resulting in....
Posters and signs that stay up all year!