Unity is created when there is a relationship between the different elements in a design or artwork. Unity adds order to a composition and helps us see it as one thing instead of a number of separate parts.
There are a number of techniques that can be used to create unity:
Although most artists and designers try to create a sense of unity in their work, it is important that compositions are not so unified and similar that they seem boring. There should be some variety within a piece of work.