The two areas you mention, word choice and structure, are the two areas that I think need the most work.
For word choice, some of your sentences can be trimmed down. Sentence structure and clause order is a bit weird in some places. You also use a few words inappropriately (Be careful if you are using a thesaurus). For example, 'renders affirmation' and 'repudiates' should be avoided.
Also, do not use contractions in an English essay or formal writing in general. This means do not write 'don't' 'wouldn't' 'shouldn't' etc. Write them out fully as 'do not', 'would not' and 'should not' etc.. Even better, try and rephrase the sentence so you avoid using the word 'not'.
For structure, it seems like you analysed the piece chronologically. While this sometimes is effective, in this case I think you could have organised your paragraphs a lot better. Specifically, try to group the same persuasive techniques into one paragraph. You can also group together techniques which are similar and thus provide a logical and smooth transition in your discussion.
For your intro, I've made a few personal adjustments. See if they sound any better to you:
Recently the government introduced a proposal to build a youth prison in the town of Nerrindera. Although the proposal has been met with public disapproval, Government Minister Donald Farthington continues to assert that the prison will benefit the Nerrindera community. In an assertive and concerned tone, Mr Farthington contends that Nerrindera residents should sympathize with young prisoners and accept the government’s proposal to build a youth training center in their town.
Your introduction is a chance to show the examiner you get the gist of the text you are analysing. While I haven't read the text, from your examples I think it does a lot more than just make people sympathise with prisoners. In particular it tries to combat public concern over having a prison within their community by portraying the 'youth centre' in a positive light. There is a deliberate avoidance of words like 'prison' that carry negative connotations.
Some other minor changes in the next paragraph:
Mr Farthington attempts to engender public approval by addressing the readers as ‘Good citizens of Nirrendera’. By beginning his speech this way, Mr Farthington presents himself as a pleasant and friendly person.
I wouldn't bother analysing the speech opening in much detail. It's more of a formality and isn't intended as a persuasive device.
He moves on to express his concerns over the peoples trepidation in having a prison at their community. The audience is thus positioned to perceive him as one that is attentive to what they think.
First, avoiding using phrases like "This positions the reader". It's overused and sounds clunky. Second, you need to give an example here, otherwise your statement is completely unconvincing.
Some general critique:
He then contradicts his contention when he tells the locals “I too would have same worries”. With this statement he makes the audience feel that their perturbation is justified.
"contradicts his contention"sounds awkward. Avoid phrasing your analysis in such a way that makes it seem like the text is contradicting itself. There is always a motive if the author makes a concession. Usually it's to make the writer sound more reasonable and the point conceded is usually something trivial.
Here the agenda seems to be to personalise the issue. This guy is a government official. This means there is likely a preconception that he is a bureaucrat out of touch with community values. By using personal pronouns he is trying to establish a rapport with is audience.
By using the term “I promise” he assures the audience that it is safe for them. Hearing this will most likely alleviate the Nerrindera citizens concerns with the proposal.
He's a government official. Do you really think just because he said "I promise" everyone's concerns are going to be put to rest? More likely, this is designed to build rapport with his audience, again using personal pronouns and specifically involving himself. It also shows he is condicent the initiative will have benefits and that he is willing to be held accountable.
He also uses positive connotations such as ‘mistake’ rather than more serious terms such as ‘crime’.
This is a very good observation and deserves a lot more discussion. He is clearly trying to put a positive spin on the issue by deliberately avoiding words that carry negative connotations.
This is consistent with your other example:
Mr Farthington now posits that the juvenile prisoners shouldn’t be seen as criminals and they ‘need to think about their foolish behaviour’.
By using positive connotations such as ‘pleasant.., open environment ‘to describe the center, he attempts to eradicate any misconceptions the audience has about the way it will look. Such connotation arouses feelings and attitudes that positions the audience to accept the idea. He also renders affirmation that ‘it will not be a high security prison with stone walls and iron bars’, but it will definitely be ‘perfectly secure’. Once again he firmly assures the local people regarding their safety which is not an issue to worry about.
Again, another use of positive spin. He is trying to combat the perception that the youth centre will be a prison. People fear having a prison within their community because prisons house criminals and no one wants to live near criminals. This is almost like the opposite of an appeal to fear. The speaker is trying to reassure the public that the youth centre is not a prison and therefore is not a threat to their security, nor will it detract from the community. The speaker is trying to paint the youth centre as an ordinary institution within the community, rather than a prison which grabs attention for all the wrong reasons. Even the term ‘Youth Centre’ is intentional. It sidesteps words like ‘prison’ or ‘detention centre’ which are unpalatable.
Moreover, Mr Farthington goes on to consider the advantages of proceeding with such a proposal. He suggests that it will benefit the community as the youth training center would ‘employ more than 50 local people’. Likewise it will benefit young inmates as they ‘will become useful members of society’ as they will work progressively for the community. At this moment the local people, if not fully, at least nearly is convinced. Mr Farthington has not only obliterated their concerns and fear but the benefits to society seem promising.
This is a clear appeal to community values. It shows how the youth centre can effectively rehabilitate its inmates and turn them into contributing members of society. The implication in the reader’s mind is that the youth centre is for the good of the community: it converts young hooligans from being a liability on society to being a contributing force. This makes the idea of a youth centre more appealing because it will ‘clean up the streets’.
This quote also sheds some light on the speaker’s target audience. It suggests he is mainly appealing to an older audience who may feel threatened by out of control youths and who have a strong sense of pride and loyalty to their community. The advantages mentioned by the speaker appeal directly to this target audience.
I mentioned your structure seems to approach the speech in a chronological order. The result is that many of the paragraphs are muddles and lack focus. It seems like within each paragraph you are constantly jumping from issue to issue. I would have organised the paragraphs based on similar persuasive techniques or arguments. For example:
1. The way the youths within these centres are portrayed: Describing them as people who have made mistakes rather than criminals. The appeals to sympathy for these inmates etc.
2. Portraying the youth centre in a positive light: 'Youth centre' rather than 'prison'. Descriptions of the centres. Benefits of the centres.
3. Community values: Benefits to the community etc.
Your analysis throughout is also quite shallow. Don't be afraid to really get stuck into all the persuasive devices you identify. Consider how you react to those techniques and what they imply to you, rather than making generalised and pedestrian comments.