Nearly everything you do in The Simpsons: Tapped Out results in XP, but certain activities can generate XP more efficiently than others. Here are a few tips on leveling up fast in The Simpsons: Tapped Out.
1) Flora and fauna and more
Placing trees, bushes, shrubbery, and other plantlife (in addition to newspaper boxes, dumpsters, and more) reward you with XP. These decorations may not generate any cash, but they do add to your town's overall rating, which increases the rate cash and XP are generated through your Springfield.
Plant some trees around your houses, around Springfield Elementary or even around the Kwik-E-Mart. The nuclear power plant doesn't have trees in the show, but yours can. Be sure to mix things up and use different types of trees so that your Springfield is well oxygenated.
2) Choose XP heavy activities
Your residents generate XP with every move they make. Don't just focus on the cash Bart and the other residents make. Check out how much XP they'll generate over the course of the activity.
If another activity offers a better balance between the two rewards, go with that one. Determine what resource you want to farm over the other, and attack it with every resident in town. Holiday updates require the same dedication. Keep those kids trick or treating during the Halloween special to ensure a steady flow of candy.
3) Friends… so many friends
Everytime you visit a friend's town, you help yourself and your friend generate XP and money. Whether your vandalizing Moe's Tavern or collecting the cash from Krusty Burger, having friends and visiting them often is the best way to level up.
Think about it. The more friends you have, the more daily activities you can do, the faster you earn XP, the quicker you level up. There are many ways to meet The Simpsons: Tapped Out friends, including the forums!
If you haven't done so already, there are a few free donuts in The Simpson: Tapped Out. You just have to know where to look.