The main points on how and when to use quotes are:
Only include relevant quotes that support the overall argument. Do not just include random quotes to try and impress the examiner with your knowledge.
Even using one worded quotes can be a powerful way of enhancing your argument. Just make sure that they are relevant to what you are saying.
Examiners prefer shorter quotes to longer quotes. To narrow a long quote down, use 3 full stops e.g. '...'. This conveys that the quote has been condensed to the most important parts.
The most important point! Analyse the quote and explain what effect this has on the reader, the atmosphere, the tone, other characters etc. Does the quote include a metaphor? Alliteration? If so, then what is the effect of the alliteration?
Here is an example of some of the above:
When Oliver exclaims, he wants to ‘die in the fields and … never come near London again’, the hysterical tone depicts the city as a threatening prospect.