- make sure you can't add movie with empty data (with spaces only);
- don't interact with DOM directly, use React as much as possible;
- make sure you described objects in propTypes;
- don't generate key on render (here is why)
- follow these naming conventions for methods
- check out what can go wrong if you pass initialize your state with props (here, here and here)
- * don't use setState several times in one function call (method) (it's better for clarity of the code);
* - optional recommendation