Ask The Yak Guide
Common Mistakes & How to Fix Them
The top 10 mistakes students make in essays — and how to avoid them.
Common Mistakes & How to Fix Them
Time to read: 10-12 minutes
Let's fix the mistakes that cost you marks
I've marked hundreds of essays. And honestly? Most of the time, students lose marks for the same handful of mistakes.
The good news? These mistakes are fixable. You don't need to be a genius — you just need to know what to look for.
In this guide, I'll show you:
- The top 10 mistakes students make (content, structure, style, citations)
- Before/after examples
- A self-editing checklist you can use before submitting
Let's dive in.
Content Mistakes
❌ Mistake 1: No Clear Argument
The problem:
Your essay describes a topic but doesn't take a position. It reads like a report, not an argument.
Example (bad):
Social media has both positive and negative effects. Some people think it's harmful, while others think it's beneficial. There are many perspectives on this issue.
What's wrong?
This says nothing. It's fence-sitting.
The fix:
Take a clear position and defend it.
Example (good):
While social media has some benefits, its negative impact on teenage mental health — particularly increased anxiety and depression — outweighs its advantages. Governments should regulate platform design to protect young users.
See the difference? The second version makes a claim and signals what the essay will argue.
❌ Mistake 2: Off-Topic Paragraphs
The problem:
You've included interesting information that doesn't actually support your argument.
The fix:
For every paragraph, ask: Does this directly support my thesis? If not, cut it.
Pro tip: Just because you spent ages researching something doesn't mean it belongs in your essay. Be ruthless.
❌ Mistake 3: Weak Evidence
The problem:
You're using dodgy sources (blogs, Wikipedia, outdated research) or not enough evidence at all.
The fix:
- Use academic sources (journals, books, official reports)
- Cite at least one source per major point
- Make sure your evidence is recent (last 5-10 years, unless you're doing history)
Before:
Social media is bad for mental health. Everyone knows this.
After:
Research consistently links social media use to increased anxiety in teenagers. Smith (2020) found that 60% of adolescents reported heightened stress related to online interactions, while Jones (2019) identified a correlation between platform use and depression diagnoses.
Structure Mistakes
❌ Mistake 4: No Thesis Statement
The problem:
Your introduction rambles without ever stating your main argument.
The fix:
End your intro with a clear thesis. Your reader should know exactly what you're arguing.
Before:
This essay will discuss social media and mental health. It will explore different perspectives and consider various research studies.
After:
This essay argues that social media platforms should be regulated to protect teenage mental health, as current design features prioritise engagement over user well-being.
❌ Mistake 5: Poor Transitions
The problem:
Your paragraphs feel disconnected. There's no flow.
The fix:
Use transitional phrases to link your ideas.
Good transitions:
- "Building on this point..."
- "However, this view overlooks..."
- "In contrast..."
- "This evidence suggests that..."
- "Consequently..."
Pro tip: Read your essay aloud. Where you stumble or feel confused, add a transition.
❌ Mistake 6: Weak Conclusions
The problem:
Your conclusion just repeats the introduction word-for-word. Or worse, it introduces new ideas.
The fix:
- Summarise your main points (briefly!)
- Restate your thesis in different words
- Show the bigger picture (why does this matter?)
Before:
In conclusion, this essay has discussed social media and mental health.
After:
The evidence is clear: social media's impact on teenage mental health cannot be ignored. By regulating platform design, governments can protect young users while preserving the benefits of digital connection.
Style Mistakes
❌ Mistake 7: Wordy, Unclear Sentences
The problem:
You're using 20 words where 8 would do. Your sentences are confusing and hard to follow.
The fix:
Cut unnecessary words. Be direct.
Before (wordy):
Due to the fact that social media platforms are designed in such a way that they encourage users to spend more time on them, it is the case that teenagers often find themselves using these platforms for extended periods of time.
After (clear):
Social media platforms are designed to maximise user engagement, leading teenagers to spend excessive time online.
Pro tip: If you can delete a word without changing the meaning, delete it.
❌ Mistake 8: Informal Language
The problem:
You're writing like you're texting a mate, not writing an academic essay.
Avoid:
- Contractions (don't, can't, it's) — use "do not," "cannot," "it is"
- Slang ("kids these days," "loads of," "stuff")
- First person (unless explicitly allowed) — use "this essay argues" not "I think"
- Vague language ("things," "stuff," "lots")
Before:
Loads of kids use social media way too much and it's really bad for their mental health.
After:
Excessive social media use among adolescents is associated with increased rates of anxiety and depression.
❌ Mistake 9: Passive Voice Overload
The problem:
Your sentences feel clunky and indirect.
Before (passive):
It was found by Smith (2020) that social media is used by 90% of teenagers.
After (active):
Smith (2020) found that 90% of teenagers use social media.
Why it matters: Active voice is clearer and more direct. Markers prefer it.
Citation Mistakes
❌ Mistake 10: Missing or Incorrect Citations
The problem:
You've paraphrased without citing, or your reference list is a mess.
The fix:
- Cite every idea that isn't your own (even paraphrases!)
- Check your reference list formatting (APA? Harvard? MLA?)
- Make sure every in-text citation has a matching reference list entry
Common citation errors:
- Mixing citation styles (don't use APA and Harvard in the same essay)
- Missing page numbers for direct quotes
- Incomplete reference list entries (missing DOIs, dates, publishers)
Before:
Social media increases anxiety.
After:
Social media use is linked to increased anxiety among teenagers (Smith, 2020).
Self-Editing Checklist
Before you submit, run through this checklist:
Content
- [ ] I have a clear thesis statement
- [ ] Every paragraph supports my argument
- [ ] I've used credible, academic sources
- [ ] I've explained why the evidence matters (not just what it says)
Structure
- [ ] My intro hooks the reader and ends with my thesis
- [ ] My paragraphs flow logically with clear transitions
- [ ] My conclusion summarises without repeating word-for-word
Style
- [ ] I've cut unnecessary words
- [ ] I've avoided informal language and contractions
- [ ] I've used active voice where possible
- [ ] I've read my essay aloud to check for clarity
Citations
- [ ] Every idea that isn't mine is cited
- [ ] My reference list matches my in-text citations
- [ ] My formatting is consistent (all APA, all Harvard, or all MLA)
- [ ] Direct quotes include page numbers
The 24-Hour Rule
Here's my top tip: Don't submit straight after finishing.
Write your essay, then leave it for 24 hours (or at least overnight). Come back with fresh eyes and you'll spot mistakes you'd never have seen otherwise.
Why this works: Your brain fills in gaps when you're too close to your writing. A break gives you distance.
Key Takeaways
✅ Take a clear position — no fence-sitting
✅ Cut off-topic paragraphs ruthlessly
✅ Use academic sources and cite everything
✅ End your intro with a thesis statement
✅ Use transitions to link paragraphs
✅ Keep sentences clear and concise
✅ Avoid informal language
✅ Check your citations before submitting
✅ Leave 24 hours before final submission
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