This year in the Var (S. France) we have a bumper crop of olives. What to do (some of us only have one or two trees) with these olives! The easiest way is to have them pressed into oil. Just take them to the local olive mill. In our local mill at Le Val, they weigh them, they give you a computer print out of the weight, next year in March on a specific day you collect your oil, but this differs from mill to mill.
The alternative way is to marinate them. Use only ripe black olives, they look nicer and are not so bitter.
Put the olives in an 8% brine, increase it to 10% after 4 days, then to 12%. The olives remain in the brine for 2 to 3 months before being drained. To preserve them, rub them with olive oil.
Pierce the olives, an easy way is to use a cork with pins planted in it. Place the olives in alternative layers with table salt and bay leaves (15% salt according to the weight of the olives), shake them regularly. They are ready to eat after 2 weeks.
Whenever you want to use them you take out a batch and doctor them to your own taste by adding herbs, garlic, spices etc.
Bibliography: The Olive Tree in France, The Olive and its Olive Oil by A.M. Breger