A short advice, you should really care about others. A good word does nothing, if you do not mean it. There is some practical things, that helps you to express yourself.

Be emotionally supportive and listen
It takes energy from you, but it worth it. When you listen someone always look into her or his eyes (and never touch your mobile phone)

Take him or her out from the everyday cycle

Going out for have some fun always make a lot of endorphin. It does not need to be a big event, just go out having some tee, in a place where nobody else is there.

Give a surprise

It could be an old (but good) book, a magazine, a pen, a lucky coin, a cupcake something that you gave value. A surprise if always the best when you not expect it

Cheer up
A hug, a joke, old pictures can always make us smile.

Be honest
Good relations are strong because you will heard the truth from your friend, but he or she never cared about them, just accepted them.

Tell them they are important for you