We’re monolinguals raising our daughter from birth to be a fluent-as-a-native trilingual/triliterate. We travel the world slowly and dip into local schools ( in Spain and Asia) to help us and find it particularly helpful for the reading and writing aspects.

She just turned 11, so we can see how well our hard work has been more than worth the effort, but she continues to work daily ( reading writing and speaking) all 3 languages.

I’ve written a lot about how we have raised a multicultural, multilingual kid. http://www.soultravelers3.com/2011/06/how-to-raise-a-bilingual-or-multi-lingual-child.html

As you say, it is indeed a process!