Get the Zen Garden and water the plants until they don't need anything else. Advance the system date ahead and the plants will need water again. Purchase new plants, grow them to full size, then sell them. Repeat this to earn more money. You can also use this technique when you have to get Marigolds in Crazy Dave's shop when they are out of stock.
Set up your defenses around the slot machine as follows: one row of walnuts on the right side, one or two rows of sunflowers on the left, and fill everything else with pea and snow pea shooters. Protect the lawn mowers as each is worth a Gold Coin at the end of the game; do not let them mow the zombies. Stop collecting sun at about 1,900 sun points. At this point, the garden should be full and acquiring the extra 100 points to win should be easy. Just collect enough sun to offset the slot machine while keeping the slot machine spinning. It will randomly drop one or three gems as long your patience lasts. If the zombies get close to the mowers, end the game. Just collect the sun lying on the field to end the game.
To make Walnut Bowling more profitable, protect the lawnmowers as each is worth one gold coin ($250). Line up shots off the front runner. After the first zombie is hit, each additional zombie strike earns you coins. Create a front runner where none already exists.Pole vaulting zombies will run fast until they vault over a nut, and the newspaper zombies run fast after getting the paper destroyed by a nut. Let them run a short distance down the lawn before sending a nut their way. You do not need to use nuts. When there are a couple zombies ambling down the lawn without a clear ricochet shot, wait a while to see if more of them will step out to play. They can always be killed once they cross the red line. Use one nut for regular zombies, three for bucket wearing zombies, and two for the others. Also, keep the exploding nuts in reserve and don't use them unless a mob crosses the line or there are not enough nuts or room to clear out a difficult to kill zombie. Use the regular walnuts for the zombies that have not reached the red line. Do not use exploding nuts to kill pole vaulting zombies directly as pole vaulting zombies only jump obstacles in their own lane. A pole vaulting zombie who has not vaulted yet will safely jump over explosions or nuts in their own lane. Find a neighbor in the next lane and time the nut to hit when the pole vaulting zombie gets close to the neighbor.