What planning should you do to visit Walt Disney World?
You should start planning your Walt Disney World vacation at least six months in advance.  First figure out your travel arrangements.  If you are able to drive, you will have your own vehicle available to travel to the parks.  If you fly, you will either need a rental car or will need to use other forms of transportation, such as uber or lyft.  Within the Walt Disney World parks and resorts there is Disney provided transportation, but it is often crowded during peak hours such as park opening and closing.  Next you will need to decide where to stay.  The Walt Disney World resorts are the most convenient, but also the most expensive option.  There are Walt Disney World resorts cater to different economic levels from more affordable up to more luxurious.  Staying on the grounds will also often allow to enter parks earlier or stay later than the general public.  Staying off the grounds is usually less expensive.  There are many hotels and resorts in the Orlando area to choose from.  Other options are to use a rental service such as VRBO or AirBnB to rent a property such as a house or condo for your stay.  Next you need to decide on how many days in the parks you'll spend and whether you will stay in one park for an entire day or want to have the option to "park hop".  Tickets are discounted for a larger number of days in the park.  The "park hopper" option is a premium on top of the base ticket price.  Often there are discount ticket websites but be careful about scams.  The safest is to buy from Disney or a licensed travel advisor.  Typically the price from a travel advisor is they same as buying from Disney.  Next make a budget for how much you'll spend on food in the parks.  Food is fairly pricy, but there are options from counter service all the way up to sit down restaurants and fine dining.  Realize that eating in a sit down restaurant will take time away from other activities in the parks.  Reservations can be made on the Disney website but are often difficult to get for some restaurants.  Taking food into the park is also an option as there are lockers available at the parks to store things.  Some items such as knives are not allowed, so plan ahead if food needs to be sliced.  Next look at the rides and attractions that your family wants to ride and make a plan for which are the most important.  A guidebook such as the Unauthorized Guide to Disney World is very helpful to provide plans for your day(s) in the parks.  These guidebooks will give you help on when the lines for attractions will be shorter.  Don't just try to show up in a park without some sort of plan as to which attractions to visit and when.  Visiting without a plan will result in frustration, long waits, and disappointment.  Also realize that you will not be able to visit all of the park attractions in one visit.  As the time of your visit approaches watch the weather reports.  Late afternoon thunderstorms are typical in Orlando in the summertime.  Most attractions at Disney World are indoors and will continue operating during rain.  Rain ponchos can be purchased in the park, but they are more expensive in park than if you bring your own.  It can also be very hot during the summer, so plan on having water, sunscreen and wearing appropriate clothing for the weather.  Be aware of how your party's attitude is during your visit.  Visiting Disney World requires a lot of walking and also requires stamina.  If people are getting tired, take a break, either in the park or back at your hotel.  Don't make your visit a "death march".  Also base the length of your stay in the park on the age of people in your party.  Young children or elderly may require longer and more frequent breaks.  One option is to go to the park in the morning, go back to your hotel in the afternoon for a dip in the pool, and return to the park later afternoon or evening.  Pay attention to the park hours to know how early you can arrive and how late you can stay.  Most parks have some sort of parade and fireworks show at closing.  Most are very worthwhile to see.  And remember above all that you should have fun.  Don't be so focused on your plan of visiting attractions that you don't take advantage of spur of the moment opportunities such as interacting with characters or getting a quick photo with the family.  Hopefully this will not be your only vacation at Disney World, and you want to have fond memories of your visit so that you will want to return again as soon as possible.