It's not really possible anymore (unless you're a genius) to be a polymath, someone who is an expert on a wide variety of topics. There's just too much out there to learn. But it's useful to know the truth about things, and people are often strangely confident in their opinions on issues they don't know much about.
So try this instead: just agree with whatever the experts of a given topic agree on. And on issues where there's a lot of disagreement among the experts, don't have a strong opinion. This doesn't guarantee you will be right, but on average it will certainly be more accurate than an uninformed opinion. And if you do have the time to become an expert on a topic, wait until you gain some of that expertise before getting the confidence to believe something outside the mainstream of expert opinion. Also, for any given topic, the weight we should give to experts should really depend on the mechanisms that exist to verify their beliefs. For instance, we should really just agree with physicists on statements that can be, and are, repeatedly tested. But it's not as important to go with the experts on esoteric philosophical topics where there's no way to demonstrate what is wrong or right. Most issues fall somewhere between the two.
Unfortunately, the news can often be a crappy place to know the issues that have widespread consensus among the experts. For instance, if there's an issue where 99% of scientists agree with one side, when a cable news show covers the topic, they will simply have someone from each side on to argue their case which will leave the impression that there's a split on the topic. If many people (but not the scientists) still believed the earth may be flat, unfortunately much of the news would probably present the topic largely as "opinions differ". Also, when it comes to getting news from pundits, they are "experts" at being successful TV personalities, not at being "right" about whatever they are talking about. So it does take some looking around to find out if and when there is a consensus among the experts on the topic, but that takes far less effort than becoming an expert yourself.
Take a few examples of topics where people widely disagree, but the scientists of the relevant subject are much more in agreement. Virtually all biologists believe in evolution. Virtually all climate scientists believe in climate change. There are a ton of things I (and most people) don't understand about those topics, so why disagree with the people who do understand them?
On political issues, when deciding how we should vote, often the relevant field of expertise is economics. Economics is not as precise a science as say, physics, but we do learn more about it over time through looking at the actual results of policies across a variety of places. And there are views commonly held by the politicians and voters of all parties that almost all economists disagree with. So shouldn't we all strongly reconsider our opinions in those cases? For example:
- Corporate income taxes are bad (sorry Democrats).
- The stimulus did lower the unemployment rate (sorry Republicans).
- The gold standard is a bad idea (sorry Libertarians).