Shooting Ultra-Wide

A level might be a good help. Reference lines in the finder can turn out very useful too.
From the technical point of view perspective distortion and tilted horizons will be the biggest problem. Oh and mind your feet. You may see them more often then you intend to.

To avoid perspective distortion consider taking the picture levelled and cutting the lower part of the picture later. Or really tilt the camera so the perspective distortion is accepted immediately as a dramatic effect.

The biggest problem with ultra-wide angles is controlling what 's on the picture. Try not to have too much on the picture. But also find some interesting foreground.
The ultra-wide allows for a really dramatic effect. On the other hand that is used and seen quite often. So I think I would also try to refrain to gain that effect too often.

You may already know a lot of this, but since you asked...

All in all I can only suggest looking at Bruiachs and Ragnheidurs stream. I think they both master the ultra-wide angle very well!

light...

Thanks! I'll see what I can manage, Will be a bit of a challenge at first but I'll have all my other lenses too!

I know both those streams very well, both brilliant and, I suppose, responsible in some way for me getting the lens...

I can certainly understand that. Both their pictures are very addictive!

And the nice thing about digital is, you can try, try and try. So I'm sure you'll have a lot of fun with your new lens, even when not all the pics will be instant keepers...

light...

PS. By the way, if by chance you should pass Dresden on Your tour, then tell, we may be able to meet then.

I bought the Sigma 10-20 about a year ago and used it as my main lens, but as tuvalu already said, you can grow tired of the effect. The first shots I usually had some parts of my body in the picture, feet or elbows. And I have never managed to get it on level :)

If you want to do some fun shots, do portraits.

The wide angle emphasizes stuff in the front and lets the background move far away. If you just have "Far away Landscape" it usually turns out an extremely boring picture (but maybe you want to show the emptyness of a desert, then it might work). Architecture gets extreme perspective distortions, sometimes it's a nice effect, most often it looks like the house is tipping over. But that you probably know already ;-)