How many lessons do we need to take? It depends of your goals and dog's behavior. Three kind of basics manners are usually done within 2 sessions.
How long is the 1st appointment in private sessions? 1 hour to 1 1/2 hour.
Is my dog too old to learn? There is no age to learn. Dogs are always eager to learn. Your dog loves to please you.
How do you train dog? Please check here to see my method which is only positive.
Prevent losing your dog!
Attach an ID tag to the collar and/or have microchip registration. Never take off your dog's collar (even at home).
Prevent your dog from escaping by controlling his environment; being aware of people coming to your house, opened gates, during your walks, when opening car doors, etc.
If your dog is lost
Contact your county rescue and shelters, vets around, pet shops, all your neighbors (include them in the search), put up posters and give out flyers with pictures, post on Facebook, contact your neighbor association. Don't despair: it might take a few days before you get your doggie back home.
This website has great references.