I would aim to turn £20K into £90K+ using Warren Buffett's 3 simple moves

Billionaire investor Warren Buffett has done incredibly well by making simple, easy-to-understand moves.

For example, his great grip, an apple (NASDAQ: AAPL), is now worth tens of billions of pounds more than it paid for. However, he did not start buying Apple stock in the 1970s or 1980s. He made this move ten years ago, when Apple's success was already clearly visible for many years.

Using Buffett's three simple methods of investing, I think I can really aim to turn a sum of £20K into a portfolio worth £90K.

Here is the way.

1. Shop for good deals and not just good deals

Warren Buffett said he considers his track record to be largely dependent on one good decision every five years or so.

He doesn't always trade. Indeed, he said that if a person does not think of having a share for 10 years, he should not think of having 10 minutes. His approach is to buy a few stocks that he thinks will do well rather than a broad selection that he hopes will do well.

Apple, up 16% in the past year alone, illustrates the point.

Having a few shares increase in value by 16% each year, it will take 11 years for a £20K portfolio to be worth more than £90K. Conversely, having a broad selection of stocks with a low growth rate will take longer.

2. Let the head rule the heart

Seriously, how does Warren Buffett do that?

He doesn't do that love Apple is also known to have avoided using the smartphone in person for many years.

Buffett sometimes uses emotional language when discussing his investments, but he is actually very logical. A large part of his research involves compiling publicly available information.

Like Buffett, I can judge Apple's popularity for myself. I can also see aspects of its business model that make it attractive as an investment. It has a strong brand, a loyal customer base, a large target market, and benefits from an organic system of products and services. Looking at its financial reports, I see that last year it earned $97bn.

However, that was lower than last year and I see risks for the tech giant including a weak economy hurting consumer spending power.

At the moment, I'm not buying Apple shares because I don't like the company but because the stock value looks high to me. When Warren Buffett started buying, the valuation looked very attractive.

3. Taking a long-term approach

After buying his Apple shares, Buffett just held on to most of them, collecting regular dividends along the way.

Warren Buffett is a long-term investor. Doing so allows him to reap the benefits of buying smart businesses for less than they seem to be worth.

Taking the same buy and hold approach, I think I could aim to turn £20K into £90K.