Mollykins, don't forget that if you are talking to a person who you don't know that well (and who is not a member of your family), you must refer to them as "vous" and not "tu". When you get to know that person better, you have to ask them if you can call them "tu". The French are a bit funny like that. We have a friend in France who we address as "tu", but it took a few years of knowing his wife before she called us "tu".
And when you go into a shop, you must always say "bonjour" to the shop assistant. The French are so polite in that way.
I think this has already been mentioned in an earlier post.
If you want to do supermarket shopping, you will need a 1 euro coin for the trolley ("chariot" in French).
Also, how about "quelle temps fait-il?" - what's the weather? Il fait beau, etc.
Il ya beaucoup de soleil - there's lots of sunshine.
"les magasins - ce sont pres d'ici? Are the shops near here? Ou se trouve le marche? Where is the market.
Frogs legs - "cuisses de grenouille"
Snails: "escargots" (but I expect you know that one).
Eau minerale gazeuse (sparkling mineral water)
Eau minerale sans gaz (still mineral water)
Definitely worth taking a small phrase book, even a small french dictionary, just to check things that you see along the street.
Hope you have a great time - we're going to the South of France in July.