Tickets for Skansen can be purchased online – it doesn't save you money, but can allow you to skip the queue, which can be a bonus during the busy periods (summer and major holidays). Also, be sure to check the weather forecast on the morning of your visit, because Swedish weather is notoriously volatile, at any time of year! And it's a good idea to browse the Skansen website ahead of your visit, to see what activities, performances, shows, etc. are happening that day. There are numerous options of things to do, so you can get a sense of what activities would be of interest to your family and then plan your visit accordingly.
Skansen is a great place to experience any traditional celebrations and holidays, such as Midsummer, Walpurgis Night, Christmas, or New Year's Eve. But be aware that these days can often be the busiest times – meaning large crowds – as well.
The museum is open year round and has its charms in any season. However, admission is slightly lower during October, November and December.