What is the difference between ~는 것 같다 and ~고 생각하다 ?Feel free to just provide example sentences.

@MinhaC
같다 is used when you're not certain, just you guess or presume based on certain things
비가 올 것 같다 (we don't know if it'll rain but after looking outside or at the thick clouds above, you might think "possibly it'll rain soon"
올 시간이 지났는데도 안오는 것이 사고라도 난 것 같다.(guessing)
생각하다 when you give your opinion (not guessing) based on your own something like experience, knowledge or so.
선생님은 훌륭한 분이라고 생각한다. (your opinion)
열심히 공부하는 것은 중요하다고 생각한다. (it's close to "believe" because you know how important it is based on your experience or your belief)