I won't rewrite it (your homework is... well, your homework), but here are a few tips: Most importantly, divide up your sentences with proper punctuation. Your first sentence is way too long, as well as unwieldy. When an action stands as a thing, or begins a noun clause, it's in the gerund (+ing) form. Check prepositions. Some are missing. Also, check your capital letters. "The" indicates something specific. A plural noun without an article indicates the general sense. Also check your uncountable nouns.

hi dear friend, Although it is your homework i rewrite it but it is only my suggestion. i think you need to work on your grammar more; you have some problems in using Gerunds. And for writing, try to make an outline of the events that are happening in a movie then put the pieces together. :) Anyhow this is the correction of your essay: I think people mostly have different concepts of how to change the world, because they can change it in different ways. Probably for a group of people saving the world means talking about God, while for others, keeping the water resources or not wasting them, is the priority. For me, changing the world is just something like helping people. The way we think and live can change our world. I think people mostly have a weird concept about changing the world because you can change it in different ways probably for a group of people saving the world is talk about god for others could be do not waste water. For me we can change it just making good actions like helping people. with little thoughts we can change everything. is this ok?

Pay it forward- Your teacher will probably discuss this move. 7 pounds- a movie suggestion