In this context the better choice is "я стараюсь что-то изменить". "Стремлюсь к переменам" is OK in the context of politics but it means you do not know what change do you want and to what end. It also implies that you want the changes to be made by somebody else or the system reform by itself rather than making the changes yourself. "Я стараюсь что-то изменить" means "I want to change the system myself".