1) Enunciate. The French don't do this, but it's useful for communication and thankfully Belgians do.
2) Adopt a Flemish pronunciation of some words - main example: Bruxelles is pronounced 'Brusselles' by Belgians, mixing the Flemish start Bruss- with the French ending -elles.
3) Some things to note especially:
- 70 = septante, 90 = nonante; but unlike with the Swiss, 80 = quatre-vingts.
- Déjeuner = breakfast, Dîner = lunch, Souper = dinner.
- Don't say 'cool' or 'super cool'. These are French and laughable anyway. Instead, say 'chouette'. This means 'owl' literally, but is liberally used to mean 'great/cool/sweet/lush/etc'.
- And the one which throws the French and taunts non-Belgian French teachers: Use savoir instead of pouvoir.
- Also use 'tantôt' instead of 'bientôt'.
4) Of course there are words fairly randomly different to standard French but people may still understand the standard French, eg GSM for portable, logopède for orthophoniste. Frequently Belgian French words are derived from Flemish eg kot = chambre d'étudiant, koter = habiter un kot, cokoter = partager un kot, etc; or are unadulterated Flemish eg krotje = petit ami.
5) Shorten words: "directement" becomes "direct", université becomes unif.
6) Use English words. But not everywhere, otherwise that'd be English, not Belgian French.
- Used where there is no direct French equivalent, eg "Pourrais-tu me donner un LIFT jusqu'au parc?" but NOT "Pourrais-tu me donner du BREAD?"
- Used where there is a French equivalent but it's not cool enough - eg don't say 'spectacle', say 'show'.
- Frequently a world-wide English word is used: in the sermon this morning, the preacher said, 'occupé de son BUSINESS'; also in football: 'half' and 'keeper' instead of 'demi' and 'guardien de but'.
- Also used for no apparent reason: 'flat' instead of 'studio (apartment)', 'pension' instead of 'retraite', 'ring' instead of 'boulevard périphérique', 'tarmac' instead of 'macadam', boiler for chauffe-eau, student for étudiant...
- Often used in Brussels (whole sentences written eg in posters) to communicate 1) the propositional content and 2) a sense of despair at being in a bilingual community.
- Thrown into a sentence for 'cool-ness'. NB As an English speaker, it is not cool for you to do this: it is ignorant.
7) Copy Vicky of Little Britain fame: respond with 'oui mais non'.
All in all, Belgian French is easier for English speakers to understand than standard French is. It is also often hilarious for an English-speaker to listen to, especially amongst students (see point 6, last part).