Formal:
* Therefore, as is evident,
* As can be observed,
* Consequently, it is clear that,
* It follows, then, that,
* In conclusion,
* Thus, it is apparent that,
Informal:
* You see,
* Clearly,
* As you can tell,
* Obviously,
* Hence,
* In other words,
* To put it simply,
The best phrase to use will depend on the context and the tone of your writing.