Each of your cats requires something different in order to take care of them. You either need to pet them, feed them, or clean them. If they don't have a thought-bubble or an angry look on their face, then they are good, but if they do, then you need to take care of them in some way.

Use the time-lapse cheat in order to finish your cat's search immediately instead of waiting all of that time for them to be done. To do this, go to the date and time settings on your phone, then set the time ahead by however many minutes it takes your cat to complete its current journey. Then go back to the game and you will be able to collect the cat's find right away. You can do this trick as many times as you want to, and then when done, you can set the time back to normal.

You can buy gems and then you can use gems to buy coins, but did you know you can use coins to buy gems? In order to do so, tap on the dog. You cn collect a free daily gems reward from the dog, but after you do that, if you have enough coins, you can use them to buy one gem. The price for a gem increases each time that you buy one.

Once you have five gems, you can unlock a new cat. The rarer the cat, the better the items that they find, but the longer that they take to find the items, and unless you spend coins, you can only send one cat out on a mission at the same time. If you don't like to do the time cheat, then send short-term cats out when you play actively, and send long-term cats out when you are offline for awhile in between sessions.

Whenever you come back from being offline for awhile, poop and other coin-earners will be strewn around the house and the yard. Tap them to clean them up and to earn a coin apiece. Oftentimes a reward cat will show up with a whole bag of coins. Tap it over and over to keep collecting coins until the coins run out.