People come to libertarianism top-down and bottom-up. "Top-down" in this case means they find some things they believe or like and those things are also libertarian, so they decide to call themselves libertarian. That's a fair start. But you can't stop there; it leaves you ignorant. Then you end up believing crazy stuff like, "It's bad that cops harm people for using drugs, but OK that they extort people to fund abortions", because you have no overarching principles that guide your beliefs.
Do seek out those principles. Children can pick and choose beliefs "smorgasbord" style, but adults should find consistency by identifying their principles and the implications thereof, and pruning or adjusting them until they are harmonious, consistent, imply what they believe (and no more), and, as best they can determine, moral. These principles are your roots. They deserve your time and effort: moral roots, moral fruits.
Once you have put down sound roots, you can go to them to answer "above-ground" questions specific to today and life in the world - "What do you think about people carrying guns?" "Should Monsanto be able to patent seeds?" "Should people have to get a visa to work here?" "Is abortion an individual right?" "How should a punishment fit a crime?" and so forth. (DBR)