How to Sound British

The short answer:  Be a native Brit

Perhaps you thought we'd come home with a British accent.  That would be kind of fun, but its not too likely, especially after we found out that Bill Bryson lived here and worked with Durham University for TWENTY years and still doesn't sound British.  But we have had a lot of fun picking up new words, or using words in ways that are not used in the States.  Here's a sampling of words and their British meaning.  (British friends, please feel free to correct me if these are wrong)

Are you alright? --To execute this one properly, tilt your head to the side, and look very concerned when asking.  It translates roughly to the American "How are you?"  And the expected answer to "Are you alright?" is "Yah, you?"  Don't be caught off guard, and don't assume you must look as if you are in pain. Its a standard greeting.
Proper--because there is a proper and improper way to do everything.  Use this to describe just about everything. "I'm going on a proper walk" "I need to make a proper cup of tea"  One brand of tea I saw bore the slogan "Let's have a proper brew" to advertise its tastiness.
Right -- Could mean: Correct, okay, sure, I'm listening, that's disappointing, yah,  ... just make sure to use it all the time
Brilliant --reserve this for things that are really great, awesome, wonderful, delightful
Cheers --Thanks, bye
Dodgy -- means about the same as it does at home, just make sure to use it every so often
Burgled-- Instead of saying your house was burglarized, make sure to say it was burgled.  Its just more fun (and more British) to say it that way.  Also can be used "I didn't want to get burgled", "I didn't think anyone would burgle me".  Burgle.  Burgled. Burgle.  Haha.  I really enjoy this word.  Burgle. Burgle. Burgle. Burgle. Burgle. Really, try saying it a few times, its hilarious.  Actually, I dare you to say "Burgle" out loud ten times in a row.
Stodgy --Nebulous term.  Used to describe certain foods.  Very unclear what this actually means, even though I think I could use it correctly in a sentence....maybe...well, maybe not.  When I looked up this word the proper definition is "dull and uninspired" or (when speaking of food) "heavy, filling, and high in carbohydrates".  But there is a lot of food that could fall under that second definition, but only certain foods are actually referred to as stodgy.
Posh --Don't use this one unless you are sure you know how to use it, and I'm not.  It has a negative connotation, generally means someone or something that is overly fancy and somewhat stuck up.  I understand (sort of) how this would be used when referring to a person, but I definitely don't understand what inanimate objects and places are posh.  You'll notice your British friends using it frequently.
Tea --Could mean a cup of tea.  Could mean dinner.  Make sure you know what you are invited for if your friend invites you for "tea".
Pudding --does not refer to pudding as you know it.  I've been talking to my hallmates, and it sounds as if American pudding does not exist here, or if it does, its called Angel's Delight (update: tried Angel's Delight and it isn't pudding).  Anyway, pudding can be synonymous with "dessert" or it can mean a moist cake like treat, or it can mean other things.  Honestly, only the British know what they are talking about when they say pudding.  If they say its a pudding, just trust them and memorize what it looks like.  That's pudding.  Same with stodgy.  Just memorize which foods are stodgy.
Jelly --Jello.  They don't have jelly as we know it, apparently.
Noodles -- This always refers to long stringy Chinese or Thai noodles.  It is not interchangeable with "pasta" which is what the Brits call anything that is not rice, Chinese or Thai noodles.
Ages -- used in conjunction with "ago", always refers to the past.  Not surprising, just make sure to use it, and always emphasize the word "ages" in a sentence.
Loads -- lots.  Again, you already know what it means, just make sure to use it loads of times.
Pants --this one is rather important to understand.  "Pants" means men's underwear to anyone British.  Don't compliment a girl on her cute pants or you might offend and embarrass someone, especially yourself.  The word you want is "trousers".  Just eliminate the word "pants" from your vocabulary in Britain if you want to avoid the chance of embarrassment
Rubbish --Because no one will understand you if you say "trash" or "garbage".  Plus you can use this to describe just about anything you are unhappy with.  "That's a load of rubbish!"
State school --public school, just because that's how it is
Public school -- really fancy private school, just because they can.  Pretty sure they switched these two just to make things confusing.

Another note about "sounding British".  There is a discernibly different accent every 25 miles.  I'm told there are some advanced vocal forensic scientists here that can actually determine which street you grew up on.  So if you want to "sound British", you'll have to decide what part of Britain.  The North, the South, York, Nottingham, London, Durham, Newcastle, Berwick upon-tweed, Pity Me, Once Brewed..... The list continues on and includes every city and village in England.  Be sure that once you've decided to sound British that you maintain a consistent accent with your supposed place of origin.  As it is, its a common pastime in Britain to guess where a person is from based on accent, so be prepared to make up a good story about where you are from if you really want to pass as British.