Yes - plan your work. Take the time before you start writing the essay to sketch out what your argument is. An essay plan can be very helpful in ensuring you do not "waffle" or repeat yourself. Write some broad headings, and then some more detailed points underneath these. Work out which quotes you know, which would support these arguments. This is the place where you are able to make connections between the points you want to make, and put your thoughts in order. This is NOT additional work. This is work that will save you time when you come to write the essay - because you'll have done all your thinking up front, and won't be trying to work everything out as you write.
So, let's imagine you were writing an essay about the theme of 'conflict'. And you decide to look at "Hamlet".
You might have headings on:
conflict with characters. Conflict with self. Conflict with power.
Underneath each heading you'd write some more detailed thoughts:
conflict with characters
Gertrude - (act x, scene y)
Claudius (quote)
Ophelia - "get you to a nunnery" (and impact of this later- conflict results in her drowning herself)
Laertes - physical conflict - duel with Hamlet
Now, you might see that you have "Claudius" written under both "conflict with characters" and "conflict with power" - so we've just found a good way to bridge between these different paragraphs. We also now know we will deal with Claudius, briefly, under "characters' but mainly, we'll write about him under "power". So, we'll number the order we will write about these points in. Claudius comes last (number 4) because we'll talk about him in our next para.
conflict with characters
Gertrude - (act x, scene y) 1.
Claudius (quote) 4.
Ophelia - "get you to a nunnery" (and later, impact of this - drowns herself) 2.
Laertes - physical conflict duel 3.
conflict with power
Claudius
When we come to write our essay, then, we might have something that looks like this:
"Hamlet comes into conflict with a number of characters in the course of the drama. Firstly, his mother, Gertrude....(some quotes and analysis). He also shows himself in conflict with ophelia....(quotes and analysis). The play culminates with a sword fight between Hamlet and Laertes, which is another source of conflict in the play (quotes and analysis). Of course, these are secondary to the conflict Hamlet is in with Claudius, who is the murderer of his father, which he seeks to avenge. Hamlet refers to Claudius as (quotes and analysis).
(new para)
"Claudius, as the king, represents power. Hamlet is in conflict with Claudius' authority directly, as well as Claudius' representatives...(and we go onto explore the theme of power)
Any essay should be well sign posted for your reader
intro - state your argument
body of the essay - where you set out that argument. Each para should have an opening thesis statement, and the para should then expand on this, using textual quotes and analysis
conclusion - where you draw all this information together (don't just repeat yourself) and reach a synthesis of your views.
So let's suppose you were doing "Hamlet" and the question was about a critical moment in the play when the hero's fortunes turn.
intro: In Shakespeare's tragedy "Hamlet" the protagonist's fortunes turn a number of times in the play. In avenging his father's death, he comes into conflict with a number of characters, and also appears, at times, to be in conflict with himself. A critical moment for Hamlet is (and then you state the scene you have picked and explain why it is critical)
main body:
para 1: "This scene is critical in portraying Hamlet as a tragic character." (you then go onto illustrate how this is the case. you'd use quotes here and analyse them)
para 2: "The playwright builds the drama in this scene in a number of ways" (you'd show us what these are, with quotes)
para 3: "The turning point in this scene is a departure from what has gone before, as we see the hero now isolated in his mission of vengeance.." etc
Conclusion: To sum up, I have shown that Hamlet is a character who evolves in the course of the play. But in this scene he is shown to be...The scene is critical in showing...
I hope this helps. let me know if there's anything not clear...