Although ~ but

Hi,

Although

2. but

He's rather shy, although he's not as bad as he used to be.
She'll be coming tonight, although I don't know exactly when.

That is the definition of although, but when I wanted to replace although with but, it doesn't sound good. I would say: He's rather shy. Of course (however, anyway, nevertheless), he's not as bad as he used to be. NOT BUT

The second one is like that too.

"Although" is one of my most troublesome conjunction! I know the meaning, but when it comes to using, I'm not confident enough.

I am now writing down some examples for myself, and I will post them later, but if you know how should I learn to use that word properly, please direct me.

Thank a lot