Some extra money can come in handy for many of us, so it is easy to see why lots of people try to earn a second income.

There are only so many hours in the day though, meaning that taking on an additional job might not be an option. Fortunately, there are myriad ways in which people try and earn a second income – and not all involve working for it.

For example, one approach is buying a portfolio of blue-chip dividend shares.

An annual income that can be in five figures

Doing that can be a highly flexible scheme, meaning someone can tailor it to their own financial circumstances.

To illustrate, say someone wants to target a second income of £300 per week. That adds up to £15,600 a year. Currently the FTSE 100 index of leading UK shares yields 3.1%, but I think a higher yield is possible while sticking to quality blue-chip shares.

In this example, I will use 5.5%. At a 5.5% yield, hitting that target would require a portfolio of almost £284k.

Taking the long-term approach to investing

That is a lot. But Rome was not built in a day. Someone could drip feed money in over years or decades if they wanted, perhaps initially speeding things up reinvesting (compounding) dividends until the portfolio hits the target size.

Doing that with £500 a month, compounding at 5.5% annually, it would take 24 years for the portfolio to get to the desired size. A long wait, yes. But things could be sped up by making bigger contributions.

Also, a second income can be helpful in retirement, not just during working years. Someone in their early 40s could take that approach over 24 years and hopefully have the desired weekly second income of £300 ready to flow once they retire.

Being practical about investing

Another approach to speed things up could be to aim for a higher yield than 5.5%. But I do not want to be too ambitious here. I am focusing on proven blue-chip shares and want to keep expectations realistic.

Another practicality to think about is how actually to invest. That could be a share-dealing account, Stocks and Shares ISA or trading app. For someone eyeing a second income in or nearing retirement, it could potentially be a Self-Invested Personal Pension (SIPP).

Whatever the choice, it is important to bear in mind the effect that fees and charges could possibly have in reducing the compound annual gain achieved by the portfolio.

Here’s a FTSE 100 income share to consider

One blue-chip dividend share on my radar right now is financial services company M&G (LSE: MNG). The asset manager aims to grow its dividend per share annually. Now, dividends are never a sure thing at any company, but this FTSE 100 firm has been delivering on its goal.

Its most recent increase was small, but the yield of 6.6% already looks attractive to me even before factoring in the potential for dividend growth.

M&G has a long-established brand, deep financial markets expertise and a customer base in the millions.

One risk I see is market turbulence leading policy holders to withdraw more money from its funds than they put in, hurting profitability.

On balance though, I see it as an income share worth considering.

What income stock do we like better than M&g Plc right now?

One of our Share Advisor analysts has just released a brand new stock report that we think is a must-read for any investor looking to try and generate potential income.

And the best bit is that you can see if for yourself, right now, absolutely free of charge!

No jargon. No hard sell. Just a clear look at an income share we think is worth your time.

Christopher Ruane does not hold any positions in the companies mentioned.