I’m a last-minute planner, I have come to realize. You’d think this habit would have hurt us on a quickly arranged trip to Walt Disney World during the height of vacation season. Not so.With some strategic use of the Magic Kingdom’s FastPass+ system and the park’s app, fellow summer intern Angelique Herring and I got into 15 attractions, saw the parade and had good seat for fireworks. And we did it all at a fairly relaxed pace at the world’s most popular tourist attraction.No one tells you how to plan a last-minute Disney trip. Every park guide tells you to plan as far ahead as you can. You can buy your Disney tickets months before your trip. You can schedule FastPasses for three rides, character visits or fireworks 30 days in advance (60 days if you stay at a Disney resort). Most people grow frustrated when they see their favorite attractions have been snapped up before they have a chance to log on.We ran into a surprising number of tourists who had no idea you can get more FastPasses after you’ve used your first three. They also didn’t know you can change your reservation if a better ride becomes available.The FastPass entrance outside the Haunted Mansion on Tuesday, July 30, 2019 at Walt Disney Worlds Magic Kingdom in Orlando. ALLIE GOULDING | TimesThe FastPass gives you an hourlong window, so you can manage your time by hitting one ride late in the reservation time and catching the early part of the next pass. Meanwhile, you can use the park’s app to reschedule the passes you already have or find a new one while you wait in line.Our goal was to get into as many attractions as possible without waiting more than 20 minutes per ride. We beat that goal every time.Angelique and I downloaded the My Disney Experience app and bought our Disney tickets on a Sunday night, two days before our trip. We scheduled three FastPasses, but we kept checking, and we ended up rescheduling them on Monday. To do this, click “Modify” on the FastPass section of the app and you can see if something becomes newly available. We got Space Mountain on a second look and bumped Pirates of the Caribbean.Theme Park Guide 2019: Everything new coming to Disney, Universal, SeaWorld, Busch Gardens and moreFastPasses for popular rides sometimes become unexpectedly available, so keep checking even on the day of your visit.Our FastPass strategy was to schedule our three reservations early in the day so we could add more passes later. You can only get one at a time at that point by using the park’s app or kiosks placed around the Magic Kingdom.Guests gather in front of Cinderella's Castle to take photos on Tuesday, July 30, 2019 at Walt Disney World's Magic Kingdom in Orlando. ALLIE GOULDING | TimesOur first three passes were for Buzz Lightyear’s Space Ranger Spin, Space Mountain and Haunted Mansion. We scheduled them back-to-back from 9:05 a.m. to 12:25 p.m. We got on the rides at the beginning of the windows, with an additional stop at the Tomorrowland Transit Authority Peoplemover to cool off in the air-conditioning and reapply sunscreen. We completed our first three rides by 11:30 a.m., just in time for lunch.Here’s where the game plan changed a bit.The minute we scanned our tickets for the Haunted Mansion — our third and last reserved FastPass — I opened the Disney app in line and scheduled another FastPass for the next available ride, which turned out to be It’s a Small World. It was available 20 minutes after we finished with the ghosts of the Haunted Mansion.Guests exit It's a Small World, while the stand-by and FastPass line continue to grow in the background, on Tuesday, July 30, 2019 at Walt Disney World's Magic Kingdom in Orlando. ALLIE GOULDING | TimeEven with the international singing dolls in hand, I kept checking the app as we made our way to Fantasyland to see if any rides that were more enticing opened up. We could have modified that FastPass on the spot if we wanted to.We kept this up throughout the day, hitting 15 rides and character visits with 12 FastPasses before 7 p.m. At that point, we could’ve kept going with additional rides, but we decided to take a break for dinner and take some videos and photos around the park before settling down for the Happily Ever After fireworks finale.RELATED: Disney World bans smoking in all parks, reduce stroller sizeAll in all, we had a good day at Disney. We didn’t overwhelm ourselves by trying to hit every single ride and attraction. We made time for necessities like food, water and sunscreen. And we still had time for the parade, fireworks and even some shopping.So my last-minute ways aren’t such a bad habit. Just sprinkle some preparation in with your pixie dust.TIPS • Bring a portable charger for your phone since you will be on it a lot.• Schedule your FastPass reservations as early in the day as possible.• Make a new reservation as soon as you finish your first three.• Look for rides with a wait less than 20 minutes between the hour-long FastPass windows. Ride wait times are posted on the park’s app.• Keep checking the park’s app to see if a FastPass for a ride you want opens up.• Attitude is everything. Don’t feel pressured to ride every single ride, and take advantage of the rides with no wait time, even if you never planned it. You might end up loving it.WHAT WE DID Here’s what we did on a busy Tuesday in July in the Magic Kingdom. Our wait times were 20 minutes at most. The bold FP means we used the FastPass+ system for that attraction:Buzz Lightyear’s Space Ranger Spin — FPTomorrowland Transit Authority PeopleMoverSpace Mountain — FPHaunted Mansion — FPIt’s a Small World — FPWinnie the Pooh — FP Peter Pan’s Flight — FP Ice cream snackMad Tea Party ride — FPPeople watching and relaxingLunch (We ordered ahead on the app to save time, and it was waiting for us when we arrived)Afternoon paradeUnder the Sea: Journey of the Little Mermaid — FPPrince Charming Regal CarouselMickey’s PhilharMagic — FPDumbo the Flying Elephant — FP Character meet and greet with Tiana and Rapunzel in Princess Fairytale Hall (our longest wait) — FP The Magic Carpets of Aladdin — FPDole Whip snack (surprisingly short wait for this soft serve pineapple treat with a cult following)Enchanted Tiki RoomDone with attractions by 7:30 p.m., we strolled Main Street, had dinner and found a spot to watch the fireworks finale.