Katy Perry's new video is all about breaking up with someone and joining the Marines. Let's all sit under a tree and review what we've learnt...

Break-up Dos and Don'ts

DO: Approach the initial conflict as calmly as possible, encourage your partner to listen to what you're saying, and do your best to listen to them too. If you're not sure how the relationship stands, a cautious approach is best and less likely to cause embarassing fallout.

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Advice for cheating boyfriends: DON'T misbehave in the window of an office building with clear view to the street

DON'T: Be like Katy Perry and storm your partner's office when you see them getting flirty with a co-worker, leave a once-loved necklace on their desk, and chuck a bundle of papers directly at their face making an unconvincingly loud banging noise before storming out. This can lead to misunderstandings all round, and may cause damage that you can't undo.

DO: Seek out a supportive network of friends after the split has been finalised, who will make you feel better about a bad situation and help you get back on your feet again.

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Maybe the Marines don't have a hairdresser there and tell you to bugger off if you turn up with long hair, we don't know

DON'T: Cut off most but not all of your hair in a petrol station and run off to join the Marines. Whilst the Marines provide an excellent group of colleagues to take your mind off the stress of a life-changing experience and a frequently-updated rota of outdoor activities, you will eventually be asked to kill other human beings and this can prove difficult, especially after a breakup.

DO: Stay active. Depression can set in, and the temptation to sit around the house eating takeaway pizza and playing video games is strong, especially now there's no-one to tell you what to do or remind you how long you've been playing. Get out and walk around, go to the gym, or look up exercise routines online.

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DON'T try this at home. Or, indeed, anywhere else 

DON'T: Engage in fully-clothed underwater wrestling. This is not only dangerous, but most swimming pools are carefully patrolled to discourage this exact form of activity. The only way you'll be able to do it is by surprising dogwalkers in the park when they go near the duck pond.

DO: Get your personal hygiene up to scratch. If you've been in a failing relationship for a long time, you might have stopped making an effort – so stay clean-shaven, make sure you wash your hair frequently, and do your level best to smell tip-top at all times with frequent baths and showers.

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DON'T: Lie down on the beach, link arms with your work-mates, and scream as the waves roll over you. Just don't do that. Ever. It looks really unpleasant.

DO: Get out there! You're not going to find another partner sat at home. Go out with your friends, join a club, take a class in something, find some people who share your interests on sites like MeetUp.com, and increase your chances of meeting that special someone.

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Pictured: overkill

DON'T: Take it too far and invade a country by sea.