You have to make sure you are encouraging behaviors that will lead to the values you want to define your culture. You can do this through rewards and recognition. You should make it harder and less socially acceptable for people to act in ways you'd like to discourage and make it easier and a point of pride for people to act in ways that align with your values.
Behavior is the elemental content of culture. If you can help guide behavior through leadership, rewards, recognition, organization design, and other systems (IT, HR, etc.), you have a much better shot at guiding culture to where you want it.
Don't be afraid to write about your culture and shout it from the rooftops. Everyone in your company should know what you are hoping for and what you are looking for. That's just the start, however. If you ask for one thing and your systems encourage people to behave in a way counter to what you are asking for, you aren't going to get the culture you want. You have to have systems in place that will help align your employees' behaviors with the values you want to see in your culture. Once you find that fit, your culture will start to emerge as a coherent and palpable part of your organization.