The art of using the internet to hold politicians to account has taken a battering over the last few days. Critics have rounded on keyboard warriors who think they can decide elections with Twitter hashtags, largely in response to the dreary, sometimes frenzied #CameronMustGo campaign. As James Bloodworth convincingly argues, “Step away from Tweetdeck, close down your laptop and believe it or not everything carries on just as it was before”.

The next slap for social media revolutionaries came in the form of Isabel Hardman’s comprehensive takedown of annoying political memes which compare and contrast parliamentary attendance during debates on MPs’ expenses and, say, cuts to welfare. It turns out a lot of the graphics are faked, actually using pictures from different debates. The evidence soon went viral.

Both of these examples provide compelling reasons why we should not believe anything we see on the internet, ignore social media and assume no bedroom crusader is ever going to change anything in politics. However, politicians who think they are safe from the online mob should not be complacent. It is certainly clear that amateurish hashtag campaigns randomly calling for the Prime Minister to quit will achieve nothing except deserved derision.

Yet the right use of social media can bring about ministerial resignations. Emily Thornberry, the Labour shadow minister who was forced to resign over her tweet sneering at the working classes, is the perfect case study. For the power of political Twitter, let me make the case for the defence.

Step one: Politician makes a serious, but not too serious error. If there is no obvious single reason for public outcry, such as with the vague #CameronMustGo hashtag, it doesn’t matter how many people tweet it, your campaign will be futile.

Conversely, if there is a very obvious reason – an affair, some proof of gross corruption – social media will make little difference, because the old media will cover it anyway. What you need is a bad mistake, but not something that is immediately newsworthy. Such was the case with Thornberry.

Step two: Creating a Twitter storm. It is vitally important, when seeking to rally the internet troops, that you maintain credibility at all times. Tone down the faux outrage; sensible people will see through it. Keep it simple, reality-based and as non-partisan as possible.

As the parliamentary attendance meme shows, any deviation from the truth will be fatal to your campaign. With Thornberry, all that was required was the addition of the word “snob” to her original tweet. This brought it to everyone’s attention, but kept it brief and let the snowball effect take its own course.

Step three: Involve political actors. Westminster is a bubble, so those in the bubble will not care about 300,000 people tweeting a hashtag unless other people in the bubble are tweeting it as well. At this stage you need more than anonymous Twitter eggs with 30 followers. A phone call to a party spokesman or a helpful politician can do the trick. That way your campaign becomes something that cannot be ignored.

A Labour spokesperson’s comment that he could see nothing wrong with Thornberry’s tweet was instrumental in moving the story along. Condemnation from senior political opponents meant the papers had a story on their hands. By this point it matters less what the hundreds of thousands in the Twittersphere think, and more the ten thousand or so within a mile’s radius of the Houses of Parliament.

Step four: Evolve the story. Tweeting the same thing over and over again for hours and days on end will merely bore your audience. You need to make sure your campaign is fresh, that new angles are found, that there is a trajectory for the story to take. A petition with 100,000 signatures will itself make no difference, but it is another thing for journalists to write about and move the story on. As is a critical comment from a charity or a respected campaigning organisation.

You may even have to leave your keyboard, go down there and stir things up yourself. For Thornberry, her off the cuff comments to a reporter denying wrongdoing were incendiary, giving news websites another headline and inspiring more journalists to get on the story.

Step five: Win the narrative. Of course, Twitter cannot take out a politician alone. But if your campaign wins the argument, controls the narrative and drives politicians and journalists into becoming involved in the story, it has a good chance of making it happen. Lose the narrative and you will lose the interest of the people you need to finish the job. Convince them you are right, convince them there is a story, and you could end up with a scalp on the front page of tomorrow morning’s newspapers.