Potion stairway

This is good way of adding color to your vault, if you can afford it:

Skeleton tip

You can use the mountains south of the desert to block skeletons and rest.

This is recommended instead of running into a cave to recover, since leaving the area probably resets the experience you have gained from attacking one.

Jail pictures

Daytime oasis

Skeletons

For characters breaking 30 life, skeletons give really good experience if you have a group of at least four people, even more experience than the Grand Shaman.

Assuming you focus on one at a time:

More oasis pictures

The main use of the oasis is to drink during the day, to avoid thirst. The depth effect and the palm trees make it look cool too.

There are interesting gameplay possibilities with water, short characters have an easier time hiding underwater, while taller characters are able to tread through deeper water without having to hold their breath. Water also slows down players. So perhaps players could use a bridge across a river and then destroy it to escape a chase.

How not to kill the Grand Shaman

Oasis

I managed to get one glimpse before being chased away by several skeletons. They are really tough.