Getting train tickets at the airport can be a hassle if there is a long queue, but while you wait for your luggage it is possible to get train tickets already. Look for the yellow machines close to the customs exit. This can save you some time.
NS.nl (website and apps) is a great way of finding out how to get from one place to the next. Also check out 9292.nl (website and apps)
Uber from the airport is sometimes cheaper than regular transport.
There are more bikes in Holland than people and you will see this as soon as you enter the city. It takes some time getting used to and watching out for the bikes. Remember to not step in the bike lane (usually clearly marked and often red). Also, bikers usually think they have the right of way, even at a crossing, so don’t assume a bike will always stop for you.
If you have kids with you it is very important to keep them close by as the bikes can go very fast down the lane and it can be dangerous for kids to play around on the curb next to the bike lane.
The best and cheapest option for taxis is Uber in the bigger cities.