How to Memorize Things Fast, and Retain Information Until Exam Day

Fast versus lasting: two different goals

If you want to know how to memorize things fast, start with an uncomfortable fact from learning research: the methods that feel fastest in the moment are often the ones that fade fastest. Rereading a list five times in a row makes it feel familiar quickly. A day later much of it is gone.

So this guide separates two goals:

• Getting it in quickly: retrieval, generation and mnemonics like the memory palace.
• Keeping it until exam day: spacing and sleep. This is what people mean when they ask how to retain information.

For a certification exam you need both: you have a lot to learn, and it has to survive weeks of new material piling on top.

Forgetting is fast and predictable. Hermann Ebbinghaus measured it on himself in the 1880s, and a modern replication by Murre & Dros (2015), with one participant over 70 hours of learning and relearning, produced a curve similar to his. Interestingly, the curve was not completely smooth: there was likely an upward jump at the 24-hour point, which the authors suggest may reflect sleep. More in our guide to the forgetting curve.

1. Test yourself from the first minute

The single most useful change is to stop reading and start recalling. Cover the answer, try to produce it, then check. A review by Roediger & Butler (2011) concluded that retrieval practice often produces large gains in long-term retention compared with repeated studying, works even without feedback, and works better with it.

Producing an answer yourself beats reading it even when the task is simple. A meta-analysis by Bertsch et al. (2007) summarised 445 effect sizes from 86 studies of the generation effect: people remember information they generate better than information they read, with an average effect of .40, which the authors describe as a benefit of almost half a standard deviation. (A standard deviation is the typical spread of scores; half of one is a meaningful gain.) A later meta-analysis of learning from texts, Schindler & Richter (2023), found a similar benefit of generation over reading, g = .41, not explained by extra time on task.

Practical version: turn every heading in your notes into a question, and answer it before you look.

2. Use a memory palace for ordered lists

The method of loci, also called a memory palace, is an ancient technique, described in classical texts on rhetoric. You picture a route you know well, such as your home, and place a vivid image of each item at a spot along it. To recall the list, you walk the route in your mind.

It does work. A meta-analysis of 13 randomised controlled trials, mostly with university students, by Twomey & Kroneisen (2021) found a medium effect of g = 0.65 (95% confidence interval 0.45 to 0.85). The confidence interval is the range the true effect most plausibly lies in; even its low end is a real effect. The authors also noted a high risk of experimental bias in the studies, so the true benefit could be smaller.

With training, the gains can last. In Wagner et al. (2021), six weeks of method-of-loci training produced more durable memories than working-memory training or no training, and the advantage was still there four months later.

The honest limits

• It is for lists, not understanding. A memory palace can give you the seven OSI layers in order. It cannot tell you why a switch works at layer 2. Certification exams mostly test the second kind of knowledge, through scenarios.
• It takes practice. The durable effects in Wagner et al. came after weeks of training, not one evening.
• Other mnemonics rate lower. The review by Dunlosky et al. (2013) rated the keyword mnemonic and imagery for text as low utility, mainly because benefits were narrow or short-lived.

3. To retain information, space it out

Memorising fast and forgetting fast is the default. Spacing is what stops it. The meta-analysis by Cepeda et al. (2006), covering 317 experiments, found that the best gap between study sessions grows as the time until the test grows. For an exam weeks away, that means returning to material after days, not minutes.

Spacing also feels worse than it is. In Kornell (2009), people learning word pairs with flashcards did better with spacing than massing in 90% of cases, yet 72% believed massing had worked better after the first session. If spaced review feels harder, that is expected. See desirable difficulties for why.

For a simple way to run spaced flashcard reviews, see the Leitner system.

4. Sleep on it

Sleep is not optional for memory. A set of meta-analyses by Newbury et al. (2021) found that total sleep deprivation before learning impaired memory with an effect of g = 0.621, and deprivation after learning with g = 0.277; the authors noted publication bias and low statistical power in the literature. Partial sleep loss matters too: Crowley et al. (2024) found that restricting sleep to 3 to 6.5 hours, compared with 7 to 11 hours, impairs memory formation (g = 0.29).

Translation: a late-night session that costs you two hours of sleep can undo part of what it was meant to add.

A 20-minute routine to memorize a new set of facts

Put the pieces together into one session. Say you need to learn 15 well-known port numbers.

1. Minutes 0-3: read the list once, slowly, and group it into chunks that belong together (email, web, remote access, name resolution).
2. Minutes 3-10: cover the numbers. For each service, say the port before you look. Mark misses.
3. Minutes 10-15: go through the misses only, then the whole list again from memory, in a different order.
4. Minutes 15-18: write the whole list from memory on a blank sheet. Check it.
5. Minutes 18-20: sit quietly. Wamsley (2019) reviews evidence that brief quiet rest after learning helps new memories consolidate.

Then come back to the same list tomorrow, in three days and in a week, starting cold each time. The first session gets it in fast. The returns are what make it stay.

What does not work as well as it feels

• Rereading and highlighting: both rated low utility by Dunlosky et al. A larger meta-analysis of the same techniques, Donoghue & Hattie (2021), found underlining and summarisation least effective (though still positive) and distributed practice and practice testing most effective.
• Studying to your "learning style": Pashler et al. (2008) found virtually no evidence that matching instruction to a preferred style improves learning.
• Cramming the night before: it combines massed practice with lost sleep, the two things the evidence above warns against.

How to use this for a certification exam

Most certification exams mix memorised facts (ports, acronyms, process names, service limits) with scenario questions that require understanding. Use the fast techniques for the first group and practice questions for both.

1. Find your fact gaps. Take a free practice test, for example the Network+ practice test or the A+ practice test. Mark each miss as "didn't know the fact" or "didn't understand the situation".
2. Facts into flashcards. One fact per card, question on the front. Review them with spacing.
3. Ordered lists into a memory palace. Keep it for a few lists that really need order, such as the OSI layers or the troubleshooting steps in your exam's objectives.
4. Understanding gaps into explanation. Use the Feynman technique for concepts you could not apply.
5. Retest after a week. Retake the practice test. Facts you still miss go back to the front of the flashcard queue.
6. Last 48 hours: short retrieval sessions only, and a full night of sleep before the exam.

For the full picture, start with our guide to studying effectively and active recall.