“This Stock Could Be Like Buying Amazon in 1997” Best shares to buy now: I believe these FTSE 100 shares could double my money Finding the best shares to buy now could be a useful exercise for any investor. It may allow them to uncover high-quality companies that trade at low prices. Over time, they may offer superior returns than other FTSE 100 shares which leads to a larger portfolio value in the long run.With that in mind, here are five FTSE 100 stocks that appear to have long-term growth potential. They could realistically double an investor’s initial outlay as a result of their competitive advantages and strategies.5G is here – and shares of this ‘sleeping giant’ could be a great way for you to potentially profit!According to one leading industry firm, the 5G boom could create a global industry worth US$12.3 TRILLION out of thin air…And if you click here we’ll show you something that could be key to unlocking 5G’s full potential…The best shares to buy now with wide economic moatsWhile deciding which are the best shares to buy now is clearly subjective. In many instances, such companies are likely to have wide economic moats. For example, they may have a unique product, strong brands or lower costs than their rivals. Over time, this may enable them to deliver higher returns that lead to an improving share price performance.Two such companies could be Diageo and Reckitt Benckiser. They’ve experienced mixed operating conditions in 2020. But both have a wide range of brands that may provide them with a competitive advantage over sector peers. As the world economy’s prospects improve, they could post impressive results that lead to higher valuations and rising stock prices.FTSE 100 shares with sound strategiesFellow FTSE 100 shares ABF and Berkeley may also be among the best shares to buy now. They’ve experienced challenging operating conditions over recent months. They may even struggle to deliver improving financial performances in the near term due to disruption caused by coronavirus.However, ABF’s budget fashion focus within retail may mean it becomes increasingly popular among UK and European consumers while their confidence is low and unemployment rises. Similarly, Berkeley could benefit from a gradual return to normality after coronavirus. Certainly with its large net cash position and dominant market position providing growth opportunities in the coming years.Meanwhile, Fresnillo may be among the best shares to buy now. The gold and silver miner is making progress on improving its operational performance after a tough period. While global economic uncertainty is high, it could enjoy attractive operating conditions that encourage share price growth relative to other FTSE 100 shares.Building a portfolio of UK sharesClearly, it’s important to diversify among the best shares to buy now. Simply owning a small number of companies could lead to an investor facing high risks and low returns. Especially should one or more of their holdings experience a disappointing period.As such, holding a wide variety of companies that operate in different sectors and regions could be a sound move. It may lead to a more resilient return, as well as the prospect of a portfolio doubling in value over the long run. Peter Stephens | Thursday, 31st December, 2020 See all posts by Peter Stephens Image source: Getty Images. I would like to receive emails from you about product information and offers from The Fool and its business partners. Each of these emails will provide a link to unsubscribe from future emails. More information about how The Fool collects, stores, and handles personal data is available in its Privacy Statement. Enter Your Email Address Click here to claim your copy now — and we’ll tell you the name of this Top US Share… free of charge! Renowned stock-picker Mark Rogers and his analyst team at The Motley Fool UK have named 6 shares that they believe UK investors should consider buying NOW.So if you’re looking for more stock ideas to try and best position your portfolio today, then it might be a good day for you. Because we’re offering a full 33% off your first year of membership to our flagship share-tipping service, backed by our ‘no quibbles’ 30-day subscription fee refund guarantee. Simply click below to discover how you can take advantage of this. Our 6 ‘Best Buys Now’ Shares Peter Stephens owns shares of Berkeley Group Holdings, Diageo, Fresnillo, and Reckitt Benckiser. The Motley Fool UK has recommended Associated British Foods, Diageo, and Fresnillo. 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. I’m sure you’ll agree that’s quite the statement from Motley Fool Co-Founder Tom Gardner.But since our US analyst team first recommended shares in this unique tech stock back in 2016, the value has soared.What’s more, we firmly believe there’s still plenty of upside in its future. In fact, even throughout the current coronavirus crisis, its performance has been beating Wall St expectations.And right now, we’re giving you a chance to discover exactly what has got our analysts all fired up about this niche industry phenomenon, in our FREE special report, A Top US Share From The Motley Fool.