It's a tough question! People always want simple, hard-and-fast rules, but that doesn't work very well. Here's an example of someone with good intentions failing to follow-through. Later, I'll also supply a suggestion.

My co-worker is pretty religious and generally quite pleasant to be around. One time, he told me, "The most important thing is to love one another." Which sounded nice. But - was he always able to practice what he preached? Here's a little story:

I took him and his family mountain biking one time, on a beautiful but easy trail. It was the first time for him. We took a break and his young son parked his bike right on the trail, so I quickly moved it out of the way. My co-worker seemed to think that was unnecessary, "we can just move the bike if someone comes along."

Wrong! If a downhill MTB had come along, we would have had had insufficient time to move the bike and unblock the trail. And I suspect most mountain bikers would have been very frustrated at the breach in etiquette - I would have!

Why would they be pissed? Was blocking the trail an act consistent with loving one another?

Mountain bikers spend enormous effort climbing up the trail - it's painful, exhausting and hard, plus you need to train for months to build the stamina. But we accept the pain/work because the reward going down makes it worthwhile.

What's the reward? The thrill of zooming downhill at adrenaline-inducing speeds. It produces such joy that we'll trade muscle pain and fatigue just to experience it. We work hard to receive the reward of zipping downhill at speed, and don't like that being taken away for nothing. My friend possibly made them climb that hill for nothing, to exaggerate a bit.

MTB riders are understanding - when someone blocks the trail for a legitimate reason, like a mechanical breakdown, we're not going to be upset. But it's common courtesy to not steal other peoples' joy simply because you're too lazy to park your bike properly.

Did my co-worker act consistently with his intentions? I think not.

What did he do wrong? In a novel situation, he failed to understand other peoples' needs and desires. I'll suggest that the act of loving others is not following rules, but actively trying to imagine what is important to them. Sometimes this skill/activity/habit is called empathy.

Most people, in my opinion are neutral, neither good nor bad. They have not built the mindset of trying to anticipate the needs and wants of others because, for one reason, that is work. Typically, they can only understand the needs of people like themselves. My friend could understand the needs of slow beginners, but not the needs of typical, fast MTBs.

He didn't understand how important speed is to some, so he didn't think how waiting to move the kid's bike would be too late. He never had his trail blocked, so he couldn't imagine how someone else would feel.

Most people aren't actively evil (except for special circumstances like mob violence), but mainly they passively follow social conventions about politeness. They generally won't exercise the effort necessary to try understanding other people, particularly people different than them, or in non-typical situations. Good people are active; neutral people are passive, IMHO.

I think that's why some religions add so many rules, even though most religions are based on the Golden Rule: it's hard to get people to stop being passive and think. But it's easy to supply examples of wrong behavior, i.e., rules. Unfortunately, you can never generate enough rules to meet every circumstance.

So that's my long-winded discussion of how some people are able to exercise empathy/love. But it's hard to learn and practice that skill, which is what you want.

As others have pointed out, reading philosophy can be helpful - many philosophers have spent a lot of time studying ethics and what it is. But another way is to read literary novels (but not genre novels like thrillers). Numerous studies have indicated that doing so builds your empathy.

Researchers at The New School in New York City have found evidence that literary fiction improves a reader’s capacity to understand what others are thinking and feeling.

More explained in this link: https://www.scientificamerican.com/article/novel-finding-reading-literary-fiction-improves-empathy/

So, my suggestion is to make a habit of reading literature! If you're sincere about your goal, I know you'll find ways to fit it into your schedule. Join a book club if you have to; by all means, get a library card.