In the past few weeks there have been some welcome signs of basic competence creeping back into the Labour operation. Three meaty policy announcements (on free school meals for all, increasing the minimum wage, and tackling late payments for small businesses) were decently prepared and served. This is a significant improvement on Labour’s announcement in January of a maximum wage cap: a policy that Jeremy Corbyn, in the middle of an interview about something else, appeared to spit out like an unexpected piece of gristle that he then tried to hide beneath his napkin.

Basic professional political competence is not enough to change the outcome of the next election, but it may help to stem the catastrophic leaking of Labour supporters to the Conservative party. What is also needed is much greater competence in attack: it is not enough to persuade people to stick with Labour; what’s important is to make it much harder for them to switch to Theresa May.

Unfortunately for Labour, with the exception of a few shadow cabinet briefs (notably from Jon Ashworth and Angela Rayner), it is hard to see evidence of any real understanding of how attack works.

For that reason, here is a very brief explanation of the minimum basic work that is required ahead of an election campaign. If the party doesn’t do the work centrally, it could be carried out by one of the trade unions that cares about winning elections, or perhaps by the parliamentary party with a little funding and some bright researchers. However, without the commitment and support of the party leadership, the work will be wasted and ineffective.

Good policy is not enough. Election campaigns require good attack. However weak Labour’s position, this is what must be done.

Do the research

Read everything the prime minister has ever publicly said or written. Look beyond Hansard. Trawl through the newspaper archives at the British Library: track down every leaflet from North West Durham in 1992, find every parish magazine in Maidenhead, every foreword to the party conference magazine when she was party chair. She was a frontbencher under Hague, IDS, Howard and Cameron: look at every vote, every speech – and, from the Commons library, get every thinktank pamphlet to which she has contributed.

From the Electoral Commission, get the records of every donation she or her constituency party received; the local party accounts; every penny in the register of interests for her and for every member of staff she ever had. Look at every foreign trip. Go to Maidenhead council and ask to see the detailed returns for her election campaigns. In all of this, you will spend many hours fruitlessly searching for something that does not exist. To do this kind of work, you need someone who understands how to research and has an eye for a story.

Catalogue

Facebook Twitter Pinterest ‘There is always money around the Conservative party and those who bring it often bring other baggage.’ Photograph: Toby Melville/Reuters

Organise your research in ways that make it quick and easy to find any topic in minutes. The research needs to be cut and diced into sections and folders so that, on any issue, you have a bunch of prepared useful quotes and votes. This will help build your understanding of her weaknesses. It will also make you quickest to react: if May raises an issue unexpectedly at PMQs, you should be able to get a list of quotes and votes into journalists hands as soon as they leave the chamber.

Build your arguments

What is your argument about May? Saying “she’s a Tory” may work at Labour rallies but not elsewhere. Build from the research a set of arguments, based on hard evidence. You need more than just a list of facts: you want to tell a story about her. How will you characterise her? Does the evidence reveal a politician who is ideological, expedient or supine? It must be convincing, carry threat and – ideally – create a contrast with Labour’s leadership.

Test. Test. Test

Take the bullet points of historical research (she voted against allowing gay couples to adopt; she opposed the introduction of the minimum wage; she voted against Sure Start etc), tie them to the threats you want to make – and test. Take the stories you want to tell about May , the adjectives to describe her , and test them. Test with polling, with focus groups, and through engagement and response on social media. Look at what messages resonate most with the groups you want to target. Find what works. What sticks. What makes them decide that a vote for anything but Labour is now a risk.

Stay focused

When you have your playbook (a list of key attack bullets, messages, adjectives) and you have done the research and done the testing, then have the confidence to stick to it. Hone the lines as you use them, but do so based on data and what works. Don’t be knocked off course. Stick to what the testing shows will work.

Share your strategy

There is no need to be secretive about the strategy. Take all staff through it. Brick by brick. Take the shadow cabinet through it. Highlight the key messages. Take the PLP through it. Show them the data. If the research is good – if the data is solid – then your strategy will inspire confidence and instil competence.

Be cautious

What you say about your opponent says more about you. Don’t punch low. Be accurate. Don’t exaggerate. Let the evidence speak for itself. Always double-check your facts.

Work with journalists

The best stories bear no fingerprints. You need to build up a level of trust with a handful of journalists at several different papers who can be relied on to treat the material fairly. Downplay what you’ve got. Give them the ingredients, but don’t attempt to cook a story for them. Never give them more than what is necessary. Never claim credit.

Two areas requiring a special tactical focus

Donors

You should have someone working full time on Tory donors. There is always money around the Conservative party and those who bring it often bring other baggage. Build up profiles of the donors, their companies, their views, and every angle on possible conflicts of interest. This will be a slow-burn so don’t expect instant results. Build the research up and hold it for now. Save it for closer to the short campaign. Build lists: top 10 donors with a connection to the NHS … top 10 donors who bet against the pound. Get this ready. Be prepared so that when one paper files one story on Tory donors in the short campaign, you have enough stories to feed the lobby for days.

Candidates

You should have someone working full-time on candidates. Get processes in place to capture the social media archives of Tory candidates before they can be deleted. Make it easy for constituency Labour parties to feed in leaflets, tweets, newspaper articles: anything that helps build up profiles of the candidates. Create Buzzfeed-type lists: 10 most outrageous things Tory candidates said about migrants etc. The goal for the team in head office is not to start fighting 500 candidates across the country but – as with donors – to build up ammunition for the short campaign. When a Tory candidate somewhere makes a mistake, you’ll have the research ready to turn a local one-day story into something that rolls on across the nationals for days.

Lib Dems

Don’t bother. If Labour gets its act together, the Lib Dems will undo themselves.

• This article is an edited version of a piece that first appeared on Medium