First, let's talk about structure. You want to state your thesis -- the opinion that you will be arguing in the essay -- in your introduction. You also want to include a conclusion that restates the thesis and summarizes the arguments you have made.
One way to make sure that you do that is to make some notes for yourself before writing, listing the arguments you will make in the essay. This way, you will know what you are going to be saying in the rest of the essay when you write your introduction.
Also, watch your time and be sure, when the time begins to run out, to at least quickly write a concluding paragraph that, at minimum, reiterates your thesis.
Now, let's look at grammar:
Which kind of services should be provide by the government and which by the community will be discuss in this essay.
Here, your problem is that the sentences is sort of backwards. Instead, you could have said, "In this essay, I will discuss..." or "This essay will discuss..." That would then provide the opportunity, in the next sentence, to state your thesis, "I will argue that..."
In general, try to write simple sentences that begin with the subject and verb rather than placing the verb late in the sentence or leaving the subject unstated.