I've been to Disney World about 50 times. These are my 7 tips for avoiding first-timer mistakes.

• Melissa Mullett has traveled to Disney frequently with her 8-year-old son.
• She says it's best to start planning a trip about seven months out.

This as-told-to essay is based on a conversation with Melissa Mullett, director of operations for David's Vacation Club Rentals. It has been edited for length and clarity.

This time of year, I see families make a common mistake. They get together for Thanksgiving dinner and think about how fun it would be to take the kids to Disney for the holidays. They commit to a trip with just a few weeks to plan and wind up entirely overwhelmed by the process.

My job is all about helping people plan Disney vacations, and I've been to Orlando many times with my son, who's 8. I've learned a lot about having a successful family vacation at Disney.

Here are my seven tips for planning a trip that is enjoyable and affordable.

Book 7 to 11 months before you visit

Suppose your family decides over turkey dinner to go on a Disney vacation; that's great. But don't try to plan a Christmas or winter holiday trip. Ideally, you should be booking accommodation seven to 11 months before your trip. That's especially important if you're staying on the property and want a resort that is closer to the monorail and the parks.

Weigh up crowd size versus events

Everyone is looking for the elusive times when lines are short, and it's less busy in the parks. September, November, February, and May are known to be quieter months. The weekend after a long weekend is always a good time to visit.

Some of the most crowded times are during events like Mickey's Not-So-Scary Halloween Party or Mickey's Very Merry Christmas Party. Despite the lines, those events add something special, so they're worth the extra wait times to many visitors.

Stay for at least 5 nights

Before you can book, you've got to decide how long you're staying. The most common length of stay I see is five nights. That gives you enough time to see a lot but also have downtime.

I definitely wouldn't recommend staying for less than five nights, especially if you're traveling with kids. If you do, you'll only scratch the surface of what Disney has to offer.

Really, a seven-night stay is ideal. That way, you can spend a day in the middle relaxing by the pool and give your feet a well-earned break.

Discuss what you want from the trip

There are lots of ways to do Disney. The most common that I see is the multi-generational trip: parents, grandparents, and young kids all off to the parks together. But there are also older teens or the DINKS — double income, no kids — in the Disney crowd.

These different types of visitors want different things. The families spend the bulk of their time at Magic Kingdom, while the DINKS visit Epcot and time their visits for Disney's array of festivals.

There's no right or wrong answer, but it's important to make sure the people traveling with you are on the same page. In my family, we sit down and run the discussion like a board meeting, where we all vote on what we do (and don't) want to do.

Check out the resources

There's so much to do in Disney that it can easily become overwhelming. Working with an experienced planner can help. There are also tons of resources online. I love AllEars, an unofficial planning resource, and Mouse Savers, which provides info on discounts.

Appoint a planner in chief

Once the group has agreed on a rough plan, assign one person to be the main planner. This keeps things moving along without too many cooks in the kitchen. The planner makes reservations, books meals, and makes a rough itinerary.

If you want to split the load, you can have two people: sometimes, my sister-in-law will book dining while I book the resorts. If you do that, just make sure you're communicating clearly. People often underestimate how far apart different areas of Disney are, which can lead to frustrations.

Pack your essentials

When the planning is done, and you're ready to go, load up on essentials. Most important: multiple pairs of comfortable walking shoes. Disney is the most walking many people ever do. I also love having a fanny pack filled with granola bars, other quick snacks, and ponchos for those unavoidable Florida rain storms.

Planning a Disney vacation can be stressful, especially if you haven't been before. But with a little research and planning, you'll have a family vacation that is downright magical.