Bilingual children, with respect to the bilingual family and learning, need to have some sort of structure. Therefore, picking a strategy early on in the process, preferably before the child is born, is important; however it is never too late. I cannot stress enough how important it is to remember that! Some people know from the beginning their children will be bilingual due to a multi-racial family or other circumstance, but many people decide later once they learn how bilingualism helps the brain development of bilingual children; along with many other benefits of being bilingual.
A few popular parenting techniques exist for raising bilingual children in an environment that promotes bilingual education. Several exist, however I will cover the two most common in this post. One thing that is fairly important is to stick with a strategy once it is started. While changing mid-stride is possible, and should be done if there is good reason, bilingual children, and really all children, like consistency. However, persevering is necessary due to the many benefits of being bilingual. While there isn't a lot of data on how many people are bilingual, we do have documented information on the benefits.
The two parenting techniques we will discuss are One Parent One Language or OPOL and Minority Language At Home or MLAH. OPOL is exactly as it sounds, one parent speaks to the child in one language while the other consistently speaks to the child in another language. There is a great book on this you will be able to find in my must have resources which is soon to come. MLAH is also as it sounds... the minority language, or the non-community language (not English if you live in the US) is spoken at home. When the family is in the confines of their home, they speak the minority language. This is just a broad overview of the two most common parenting techniques for bilingual children. I will do a specific blog post in the future on each technique complete with all of it's respective pro's and con's.
To promote bilingualism at home is a necessary step for parents wanting to maintain the minority language. It's helpful, but not necessary, if both parents speak the minority language; at least to some degree. In my "must have resources" there are multiple free and paid resources to help learn your spouses language better while you can both help educate the child in a bilingual way!
Good luck in your bilingual education and remember... keep on living bilingual!