sort out
Separable
Organise something or solve a problem
We need to sort out the problem before Monday.
Usage
Very common in British English; American speakers often say 'work out' or 'figure out'.
Separable
The object can go between the verb and the particle: turn the light off, or turn off the light. When the object is a pronoun it must go in the middle: turn it off, never turn off it.
Practise it
Add it to your daily practice or see every verb with up.
Further reading: sort out on Wiktionary (CC BY-SA).