I played Tewniletes (http://nifflas.lpchip.nl/index.php?topic=5264.0) today. The desert section was so simple and beautiful, that I felt like making a companion to my savanna tileset (http://nifflas.lpchip.nl/index.php?topic=4150.0). It's a Sahara type the Hoggar desert. I think it's looking good so far, but it's a tad boring. I'm not sure what I could add. Suggestions are welcome.
Edit: It's finished now! I have no plans to use this at the moment. Feel free to use, edit, and borrow from for your Knytt Stories levels. Please give credit. Thanks once again to everyone who contributed constructive criticism and ideas.
For a desert-type tileset, it seems kind of square-ish. Perhaps some more rounded tiles would be nice.
While curves would be more accurate, speaking purely as a player they suck to encounter ;)
Maybe you could add some plant life to this? Depends on what kind of desert you're going for, I guess. Some rocks would be a nice addition too.
They're both pretty good suggestions for a desert in general but I think, given the Sahara-style theme, they could be a little too far from the concept. Any significant amount of plantlife would make it look more like the Kalahari or Mojave; any significant amount of rock (even rocky outcroppings, which was my first thought on reading your suggestion) would make it start to look more like the interior of the Atacama.
Looking at some images, I take that back. The Sahara turns out to be a pretty varied environment. :D
I guess the answer would be sparing use of any (or all) of the suggested possibilities and even water features;
Tadrart Acacus - A rocky part of the Sahara in western Libya
(http://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Libya_4985_Tadrart_Acacus_Luca_Galuzzi_2007.jpg/800px-Libya_4985_Tadrart_Acacus_Luca_Galuzzi_2007.jpg) (http://upload.wikimedia.org/wikipedia/commons/c/cb/Libya_4985_Tadrart_Acacus_Luca_Galuzzi_2007.jpg)
Ahaggar - An oasis in front of the Hoggar Mountains in southern Algeria
(http://upload.wikimedia.org/wikipedia/commons/1/17/Hoggar8.jpg) (http://upload.wikimedia.org/wikipedia/commons/1/17/Hoggar8.jpg)
- A nearby, relatively verdant area without an oasis
(http://upload.wikimedia.org/wikipedia/commons/d/d6/Hoggar_Desert_%28Algerie%29.jpg) (http://upload.wikimedia.org/wikipedia/commons/d/d6/Hoggar_Desert_%28Algerie%29.jpg)
Ubari - An oasis lake in southwestern Libya
(http://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/Oasis_in_Libya.jpg/800px-Oasis_in_Libya.jpg) (http://upload.wikimedia.org/wikipedia/commons/f/f5/Oasis_in_Libya.jpg)
How many features of these sorts one could fit in while maintaining the feel of it would depend on the total size of the desert area in any given level. Separating any of the "busier" areas with relatively desolate sections might help maintain the atmosphere you're looking for.
Ancient ruins are, of course, the classic videogame answer to "livening-up" an expanse of desert but might be incompatible with your ideas for it.