General "up":
* arriba (most common)
Other options:
* encima (on top of)
* sobre (on top of, above)
* hacia arriba (towards up)
* en alto (high up)
* de pie (standing up)
Example sentences:
* Mira arriba! (Look up!)
* El libro está encima de la mesa. (The book is on top of the table.)
* El avión está sobre las nubes. (The airplane is above the clouds.)
* El sol está saliendo hacia arriba. (The sun is rising up.)
* La torre es muy alta, está en alto. (The tower is very tall, it's high up.)
* Levántate, ponte de pie! (Get up, stand up!)
It's important to consider the context and use the most appropriate word.