Also:
Never run. It ruins your grass. Set down patterns for designated paths.
Talk to the sewing machine lady every day, eventually you become friends and she lets you read pattern QR codes.
these two are very important, should have done the first one myself back when i played a lot (as in, a few months ago. my town is probably a wasteland ;-;)
it'll take about a week or so for the sewing machine lady to let you read QR codes, but when she does, that's the best time to start laying down designated paths, as you can find a lot of nice path patterns online.
also, the 3/2DS has a feature that allows you to collect "play coins" when you walk with the device in your pocket, up to 10 coins a day. these coins can be used in many games, such as the streetpass games that come with the 3/2DS, and animal crossing. i don't think you can start getting these items right off the bat, but at some point in the game, the sort of "general store" of animal crossing will start selling fortune cookies that can only be bought with the play coins. when you buy a fortune cookie, you get a fortune, which you will read right then and there. then, that fortune can be given to whoever is running the store at the time for a rare item. most, if not all, of the fortune cookie items are references to other nintendo games. even the fortunes are made to hint at the item you'll get for it. for example, one of the fortune cookie items is majora's mask, and its fortune reads, "If you leave my mask out there,
something terrible will happen!". that's a straight up reference to the game. if you don't want to walk around to get play coins, you can just put your 2ds in sleep mode and shake it up and down until you get your 10 coins for that day.