1) Find something to be annoyed about. It's the UK in 2015, this should be easy. If not, go on Twitter for half a millisecond. Bad customer service can be found with minimal effort.
2) Be aware that nobody cares, least of all the organisation in question. They might give empty apologies or 'gestures of goodwill' but this is merely to placate you. Nothing will improve.
3) This is especially true of rail companies. What are you going to do, boycott them and drive your own train? No, and they know this too well.
4) Your letter will be read by somebody earning minimum wage, who has a strict time limit in which to copy and paste a standard response. The best you can hope to do is brighten their day - for example, by including humour in place of hyperbolic cliches about "going to the press."
5) The press definitely don't care, unless your complaint fits their agenda. You also risk giving them ammunition - one man complained after he realised that four-digit PIN codes for voicemail would be painfully simple to hack. In absolutely no universe can it be said that the newspapers put this information to good use.
6) Accept that you are most likely to receive an unsatisfactory response, and write principally for your own amusement. If you are lucky, the person who reads your complaint will enjoy it and pass it to a colleague to read. You can also post it online, with a view to possibly entertaining a wider audience.
7) Social media audiences, of course, are keener on cat GIFs than they are on reading several pages about some largely trivial issue - however wittily you think you have worded it. Counter this potential disappointment, by writing principally for your own amusement. Even close friends and family will probably wait until you are dead before wistfully trawling through it all.
8) Be specific about what you expect. I asked one company for a three-figure settlement. They offered a lower sum, but it was still more than I had paid in the first place. In modern parlance, this is #winning.
9) The corollary to that is, you will often be reimbursed in vouchers which tie you into using the very shops or services that irked you in the first place. You can always give these away, or burn them and do a triumphant dance around the flames.
10) Avoid swearing, unless you want to instantly lose your argument. Once your reasoned logic has been stonewalled with the ubiquitous line about "company policy", and when it is obvious you will get no further, feel free to fucking let loose.
Jordan's strangest complaint related to the unexplained appearance of a single shoe in his hotel room. His personal favourite complaint involved asking Morrisons if they are breeding underwater cattle.
You can read all of these, and more, on his blog: https://embracetheabsurdity.wordpress.com/#letters
Jordan R.A. Mills - (J)ordinary World is on at Yesbar, 12th March 2016, at 16:45. Tickets cost £5 and can be purchased here.