What does it mean to be "open to life"?
In the narrow sense it can mean trusting God to not give you more kids than you can handle--whether it be 2 or 10. This requires faith that if God gives you a child you will be able to afford it, though some lifestyle adjustments will be necessary (the adjustments are also part of being "open to life"). It also means that if that child is diagnosed with a disability it should still be welcomed into the world and loved.
Another way to be "open to life" is to oppose the "culture of death". The greatest human rights tragedy of our lifetime is the acceptance of abortion as a right. Pregnancy is considered a disease that should be prevented by free contraceptives or abortion on demand. We should be "open to life" wherever it is--even the womb of a stranger.
If you are "open to life" then you shouldn't vote for politicians that support abortion, nor should you support charities that funnel money to organizations that perform abortions. You could also become an activist by praying and protesting outside the local abortuary.
We can be "open to life" by helping pregnant women. Support your local crisis pregnancy center by volunteering or donating. Encourage pregnant women that you meet. Thank her for her sacrifice. Get her name and pray for her daily.
And finally, we can be "open to life" by helping the single mom next door. Find ways to make her life easier. Give her gift cards for the grocery store or take a meal over. Pick up a box of diapers when you are at the store and drop it off. Perhaps she had contemplated killing her baby, but took the brave step of keeping him--don't let her regret making the right choice.
Being "open to life" doesn't stop with your own household, but includes all the children around you--born and unborn.