A few life changing or defining topics, products, books, etc. in no particular order.
Jane Eyre by Charlotte Bronte: favorite book
A personal relationship with Jesus Christ.
The Bible
On Becoming Baby Wise by Ezzo, breastfeeding: Yes, I agree with the premise of the book and have successfully nursed 3 children all of whom slept through the night by 3 months.
Godly parenting supported by print resources such as those by Dr. James Dobson and Focus on the Family.
Being the best Homemaker I can through management of time and resources. Finding Your Purpose as a Mom by Donna Otto and time management strategies by Emilie Barnes have helped.
Beth Moore Bible studies.
Homeschooling. I like the Charlotte Mason method and use resources from Ambleside Online.
Being committed to a local group of Christians. My particular favorite is Trinity Fellowship Church of Plainview, TX