A first attempt at B&W

[Mito]

I was more interested in the shape of the cloud against the forms of the mountains and trees. I added a touch of sepia. Did I do right or what could I have done to improve it, apart from not taking it in the first place?

[Donald]

I was more interested in the shape of the cloud against the forms of the mountains and trees.

And for a first attempt at B & W that's a pretty good way of thinking about it.

For my taste you've overdone the sepia tone, but that is always a matter of personal preference.

[Mike Buckley]

I don't think you have overdone the toning, especially if that is the look that you are going for. However, I would call it gold toning rather than sepia toning. The sepia look is more red-brown.

Notice the bright light where the mountains join the sky. That appears to be the result of post-processing rather than sunlight if I understand the direction of the light properly.

[Mito]

Thanks to you both for the comments, much appreciated.
I'll recolour the sepia, the problem is that at the moment all my PP is done on a cheap laptop so the colours you see are certainly different to those I see.
The sun was where the bright light is. I darkened the scene down and increased the contrast to hopefully give a more dramatic effect.