Here are some tips from Tony to help you make your own apronyms:
Get, and use, a thesaurus. Frequently you will know just the right word to express a thought, but it will begin with the wrong letter.
Think in phrases/groups of letters. It can ease the process if you can fit an existing phrase into your apronym, for example "ing" can be "Is No Good", 'ish' can be "I Suggest Helpfully". These may be useful to finish an expansion.
Try not to use words with Xs or Zs. These can be too difficult to match creatively, and unrepetitively.
Use British-English or American-English spellings interchangeably. It may be useful to you to have an extra letter at times or to have one fewer at others.
COLOR as against COLOUR
Collection Of Light Originates Rainbow
Try to make the expansion fit the acronym - See COLOR example, where color and rainbow go together. If the expansion fits the acronym then it is counted as an apronym.
Try to keep the use of extraneous words to a minimum. Words in brackets (although frequently unavoidable) take away from the impact of an expansion.
Remember that a hyphenated word can be used for the expansion of either one or two letters.
Half-baked could be used for 'H' or Half-Baked for 'HB'. (Although I'm not sure how often you'll find a word containing 'HB')
If stuck for one particular letter, try amending one or two others you already have words for. Changing the meaning you're aiming for can assist in matching the stray letter.
Begin by modifying existing apronyms to suit your own particular needs... sometimes changing one word in an expansion can make it so much more fitting. Remember: No apronym is so good that it cannot be improved!
Always explain your apronyms when using them for the first time with a new correspondent.....they may not understand, or worse, they may have a different and/or opposite meaning in mind.
Long words are easier to expand than short ones. They give more scope for word play.
If you must use a rude word, try to do so humourously... remember that not everybody shares your ethos/sensibilities.
Bear in mind that English may not be the primary language of your audience. Don't rush into anger or laughter at what 'you' may be misinterpreting.
Don't wait until you need one to create an apronym. Collect or create them in advance. The very time you need one will be the time you get a mental block. Having some at the ready will look better
Broaden your vocabulary. Browse through your dictionary picking up new words and new meanings for ones your already know.
If an expansion won't work out, try modifying the base word. Pluralise it, past tense it, adjectivise it, misspell it on purpose - change a 'c' to a 'k' or an 'f' to a 'ph' or even an 's' to a 'z' (it may make a difference).
Use a commonly-known foreign word if it helps.
Avoid spelling out rude words fully in an expansion. They can be typed with asterisks if you really need to include them. As I do here with 'r*d* w*rds' - the asterisks usually take the places of the vowels.
Have fun..... this is probably the most important tip.... one of the main purposes of this stack is to create a bit of mirth!
If you think of any apronymising tips which aren't listed here, please email them to firstname.lastname@example.org so that they can be included in this list.