Walking
When you take your puppy out for a walk, he sniffs out gifts, which range in type from dog toys to supplies to home décor. You can hang on to these items, or turn them into cash. To maximize your gift flow, walk your virtual doggie as you walk in real life by selecting ̶0;Pedometer̶1; from the ̶0;Go Out̶1; menu and sticking your 3DS in your pocket or purse as you stroll. If you pass by other 3DS devices on your walk, you'll StreetPass them. When you StreetPass other 3DS owners, their Miis -- or digital avatars -- will show up in your walks, and they'll sometimes even offer you gifts. Take long walks and seek out side streets for rarer, more valuable items.
Selling Items
Select the ̶0;Shopping̶1; option from ̶0;Nintendogs + Cats̶1; menu to visit a selection of stores, including a basic pet supply shop, an accessory store, a home décor center and a secondhand retailer. At each store, you can sell items in your inventory for instant in-game money. At the secondhand store, Mr. Recycle, you can opt to exchange your goods rather than sell them.
Competing
Entering competitions is a major source of cash in ̶0;Nintendogs + Cats.̶1; When you enter and win disc competitions, lure course contests and obedience trials, you have the opportunity to earn both money and Trainer Points when your puppy places. Increase your chances of a healthy cash prize by bringing your puppy to the park or the gym to practice when you select the ̶0;Go Out̶1; option. Select ̶0;Competition̶1; from the ̶0;Nintendogs + Cats̶1; menu to begin competing.
More Tips
Some of the rarest items in the game, including exclusive collars and costumes, are available at the Rare Shop, which you can only access when you take your puppy on a walk. Money isn't all you need to see everything in ̶0;Nintendogs + Cats̶1; -- you can also unlock new content by earning Trainer Points, which you get for performing day-to-day tasks and entering competitions. Although the process for earning money and points is the same across all versions of the game, you can get different items in different versions, such as ̶0;Nintendogs + Cats: French Bulldog & New Friends̶1; or ̶0;Nintendogs + Cats: Golden Retriever & New Friends.̶1; Dogs are the money-makers in ̶0;Nintendogs + Cats̶1; -- you'll have an easier time earning money if you start with a puppy and add a kitten later.