One of the most important tips to having a happy family after children come along is to make sure you still put the marriage first. The relationship between you and your partner must still be the first priority in a family. There are a number of families where the children come first, a situation that essentially leads to them becoming the primary provider of love in the household, which is both an unfair burden for a child and very bad for families in the long term.
After all, children will eventually move out of the home and get on with their own lives, which can cause big problems if the central relationship has been neglected in the years since the children came along.
Another good tip is to make sure that the family has a number of unifying activities that everyone can take part in together, such as bedtime stories for younger children or perhaps reading one chapter from a novel with an older child.