If you like to avoid crowds when you travel, this probably is your least favorite time of the year. Long lines greet you at the airport, in the hotel lobby and at your favoritenrestaurant. The beach is so crowded that you can't even find a place tondrop a towel. Everyone's on vacation.Timing is everything"There are many ways to avoid the crowds this summer," says Michael Herber,nfounder of website Whentobewhere.com, a guide for travelers who time their vacations. He says if you have to take a vacation during the frenetic vacation period, you can still choose less busy times to be out and about, which will help you avoid the worst of the lines. For example, if you're trying to find a table at a favorite restaurant, try scheduling a late lunch or an early dinner. Same thing for your trip to the beach. Think early morning or sunset. You might also avoid a sun burn. A little planning can prevent a lot of stress, according to Sanam Hafeez, a New York neuropsychologist and teaching faculty member at Columbia University. "It's important to be very real with yourself and avoid putting yourself in situations where there will be crowds," she says. "Timing is everything."For instance, if you're headed to famously crowded Manhattan this summer, a little research can reveal the most efficient mass transit options for you. It's better than languishing in a taxi, in the heat. Also, avoid rush hour when local commuters are hurrying to work.