I do think that good, protected bike lanes are critical. But I also think that a motivated citizenry that wants to take back its streets can do so without the infrastructure coming first. There are many ways to build a culture of bicycling in your community, and through that you can drive the expansion of bicycle infrastructure.
And one key to that, in my opinion, is making bicycling something that you do without any special clothing or style. Biking should be like walking, something you do in your normal work clothes, dress clothes, or casual wear.
Many people think that Holland has always been covered in bike lanes. It hasn't, but that never stop the masses from bicycling.
1950 Holland, before its cities were lined with bike lanes (Treehugger)