It is an amazing and wonderful thing that in all things that truly matter, all you will need to know on that subject is found in God's Word: The Bible.
In the case of love, read 1 Corinthians 13
You will know how to recognize when true love is given.
And when you offer true love to others.
For me, the greatest eye opener is verse 5: "(Love) does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs."
How many times have you listened to or gossiped about others or talked about your friends or family behind their backs? That dishonors those you say you love and care about.
How many times have you or someone you know been very easily offended or hurt by someone they love? A friend mis-speaks, you don't give them the benefit of the doubt and become angry. Your friendship is not in jeopardy over a mis-understanding----you need to be slower to anger. Trust that your friend means you no harm. I have seen the same with siblings---ever get angry for no real reason with your brother or sister?
Do you hold grudges? Do you think to yourself the next time they do this same stupid thing I am going to let them have it? Do you keep score and not realize it? Love does not keep any record of wrongs---it forgives---over and over again.
This is not to say you should be a "door mat" and let everyone walk all over you or push you around---anyone doing that is NOT your friend or loved one! You should love them as Christ does, but you can still avoid them, leave them alone. Protect yourself---but always love them.