We have some exciting news to share! The Motley Fool UK has now become The Twelfth Magpie -- an independent, UK-owned company, led by our long-serving UK management team — Mark Rogers, Chris Nials and Heather Adlington. In practical terms, it’s the same team you know, now fully focused on serving our UK readers and members.

Just as importantly, our approach remains unchanged: long-term, jargon-free, and on your side. This site is our new home, and there will be extra tweaks made across the coming few days as we settle in. So if anything looks a little off, please bear with us!

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

Here’s how I avoid these 5 big mistakes when looking for the best shares to buy

When I go looking for the best shares to buy, I remind myself to avoid these simple mistakes that could harm my portfolio.

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

When hunting for the best shares to buy, simply picking out my favourite companies isn’t enough. I also work hard to avoid making some basic investment mistakes.

Tim Bennett, head of education at investment firm Killik & Co has drawn up a list of the top errors investors make. Here are the five I focus on.

XXX

Failing to diversify stocks

I used to pack my portfolio with the best shares I could find to buy at any given moment. Now I’m more preoccupied with striking the right balance. As Bennett points out, no company is immune to single stock risk. Up until 2010, oil giant BP was the largest UK stock and biggest dividend-payer. That ended with the Deepwater oil spill. No firm is too big to fail, so I spread my money around. However, even the most diversified portfolio isn’t shielded from a widespread market crash.

Being ruled by emotion when buying and selling

I try to keep a lid on my emotions when deciding the best shares to buy, but it isn’t easy. That’s one reason I avoid investing in penny shares, as even small movements can have a big impact. I also try to avoid shares that have raced ahead of the market, for fear of jumping on the bandwagon too late in a desperate bid to play catch-up.

Setting limits on the best-buy shares

I used to think setting up stop losses was a great idea. If the stock rises, you keep all your gains. If it falls, you limit your losses. The only time I did it, my stock fell sharply, triggering the stop loss, then rebounded even faster, by which time I was locked out of all its gains. Never again.

Choosing what I think is one of the best shares to buy then setting up a market order to sell once it hits a target price also seems odd. Why set an upper limit on my potential gains?

Letting others decide the best shares to buy

This is a tough one to avoid. Everybody has the herd instinct in them. It’s a necessary survival strategy, but doesn’t work so well when looking for the best shares to buy. By following the crowd I’m likely to repeatedly buy high, then sell low.

As US billionaire investor Warren Buffett famously made clear, I need to do the exact opposite by being “fearful when others are greedy, and greedy when others are fearful”. But that’s easier said than done. And if everybody adopted that strategy, he would have to reverse his mantra.

Getting stuck on old data

Investors can be prone to latch on to past data points that no longer reflect market conditions, Bennett notes. I’ve done that myself, after choosing one of the worst shares to buy rather than the best, grimly hanging on in the hope I can claw back my losses. These days, I’d rather sell and seek better opportunities elsewhere.

Harvey Jones has no position in any of the shares mentioned. The Motley Fool UK has no position in any of the shares mentioned. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

Friends and sisters exploring the outdoors together in Cornwall. They are standing with their arms around each other at the coast.
Investing Articles

£503 buys 14 shares in this FTSE 250 stock that returned 23.9% annually for the last 15 years

This FTSE 250 stock has averaged a huge return for 15 years. At today's price, £503 buys 14 shares. But…

Read more »

Black woman using loudspeaker to be heard
Investing Articles

£1,000 buys 25 shares in this FTSE 100 stock that’s returned 29.2% annually for the last 10 years

This FTSE 100 mining stock has returned close to 30% a year for a decade. At 3,995p, £1,000 buys 25…

Read more »

Female student sitting at the steps and using laptop
Investing Articles

Down 47%, is this growth stock finally worth buying in May?

With a £288m order book and a hidden pipeline of defence and nuclear contracts, is this growth stock now too…

Read more »

House models and one with REIT - standing for real estate investment trust - written on it.
Investing Articles

2 REITs yielding 7%+ to consider for passive income in 2026

A REIT backed by the NHS and another backed by Tesco and Sainsbury's with both yielding 7%+. Here's why I'm…

Read more »

Woman riding her old fashioned bicycle along the Beach Esplanade at Aberdeen, Scotland.
Investing Articles

Just 97 shares of this UK dividend stock generate £238 in passive income

A 5.7% yield, £238 in passive income from just 97 shares, and one of the most divisive dividend stocks on…

Read more »

ISA coins
Investing Articles

£10,000 in an ISA generates a second income of…

The London Stock Exchange is home to some of the world's most generous dividends. But how big a second income…

Read more »

Shot of a senior man drinking coffee and looking thoughtfully out of a window
Investing Articles

Expert recommendations: 2 top income stocks yielding 7%+!

With yields of 7.2% and 7.8% respectively, these two income stocks are catching the eyes of institutional analysts. Should investors…

Read more »

Illustration of flames over a black background
Investing Articles

3 top income-focused stocks to buy in May 2026, according to experts

Looking for a stock to buy for income in May 2026? Experts have flagged these three UK dividend shares as…

Read more »