Compliments should be specific, yes. Compliments on effort, things someone's chosen: style, hair color, art, work output, aesthetic, an outfit, are all going to feel better than a compliment on something you didn't choose for yourself.

For example: "That haircut looks great on you!" Better than, "wow, I love redheads! You're gorgeous" because the second one makes it all about the speaker having a reaction, and not about giving a no strings attached gift to someone.

I'm really digging into the ethics of compliments and I'm gonna try and stay conscious of what impulse is driving me to give one. It should be about raising someone up, you know?