Try to earn the trophy in the Baseball Field when you all five characters available. Although it requires 30 minutes, your chances of actually getting the trophy will increase. Try for the best possible chance available. If you fail to get the trophy, you will still get the listed amount of stars and coins.
Coins
You can earn coins easily through the Want Ads. Learn the requirements and craft the requested items to earn coins fast. You can tap the "X" button and wait a few minutes to refresh the list. You will also get a Special Delivery requirement occasionally that will reward you with extra items if completed within the time limit.
Crafting
Focus on crafting with the following priorities: quest requirements, city expansion or inventory, then Want Ads third. You will eventually have enough for Want Ads and earn more coins. You can craft multiple items at the same time. Although you cannot queue multiple items, you can queue different items at the same time. Do this and focus on the more complex items that require more materials first.