Waxy leaf weaving is a skill that could benefit from practice, but totally doable.

She has relevant skills and practice, and is very willing to practice with the local specifics. She works, looking around as she does for further happenings in the environment.

Further changes in the environment include the flock of floaty things deciding to float off somewhere else, and nighttime.

How dark does it get at night? Are there light sources?

There's a moon, not a huge looming one or anything. There's stars. It's pretty dark though. A few of the alien plants bioluminesce.

She watches for a little to see if any dangerous-looking things appear with the night. If not, she wraps herself in the white sheet and sleeps.

Nothing more dangerous than the wind, which is mostly calm but occasionally flares up in a seemingly random direction.

Unless it's strong enough that she needs to tie herself to something, that does not seem like a danger. She sleeps. 

The dawn comes uneventfully. The landscape of distant islands and colonies of critters is different now.

She wakes up. She notices the changed skyscape.

Do the islands seems propelled by the wind, or something else? Can she time about how fast the one she is on moves?

The islands are riding the wind. They're moving relative to each other pretty slowy, and without good reference points it's hard to tell exactly how fast.

She continues weaving and looking around, with breaks for food and water. 

That might be a ship in the distance! It's moving relative to everything else at a fair clip, at any rate.

Is it doing anything obviously suggestive of being the kind of ship whose attention she wouldn't want to draw? (Something that would look like this world's version of a pirate flag, or corpses hanging somewhere, or so on).

Nope. It's a ship, it has engines - it does look a lot smaller than the one she was left here by, and the lift envelope has an odd swooping shape that narrows to a point at the front.

If that has significance it is not something she can know. And she could try to wait for Mia, but - less likely to cause a fight, this way, if anything.

She hangs the white sheet on the tree she thought would be best for it, arranges it to blow out in the wind, tries waving to draw more attention.

The ship doesn't seem to notice her at all! It doesn't bother turning or anything. In about half an hour, it slips behind clouds.

That seems the sort of thing that might happen. She goes back to weaving and looking around. Once she's doing it well enough, she'll stop weaving practice squares and start on a cloak. 

This will make a pretty stiff and heavy cloak. It'd make a good wide-brimmed hat, though. Something like a woven shelter might suit better.

The intent is not as much comfort or protection from the elements as it is covering her clothes from first glance (the previous response to her seemed to be brought on by her clothes and her hair both, and she cannot change the former as she can the latter.) She'd considered the white flag cloth, but she has no good way to cut it or stitch it, and also needs it.

Well, a crude but serviceable cloak is within her grasp with some effort.

Around noon it drizzles for a little while but doesn't properly rain. Enough to make everything annoyingly damp but not really enough to refill her canteens with.

Just after that, a large floating jellyfish-thing covered in green fuzz visits the island and gorges itself on the grass with the floating seeds. It doesn't seem hostile - it barely even has teeth.

She has effort to give. 

She hides under trees and uses the in progress cloak for cover if it's needed.

Not hostile is helpful. 

She eats onions (and scatters seeds if she can) and berries and some of the given food, and drinks some water, and weaves, and looks around. 

And the peaceful, sparse sky fades into afternoon. One of the new islands in the distance seems to be inhabited. It looks like there's a few buildings and maybe a crop field, at any rate.

Flag and waving? (She drapes herself in what she has of the cloak.)

They shout at her! It's hard to make anything out clearly due to the distance. "Hello! We don't have a ship! Good luck!" is the only message the farmstead-or-something manages to get to her. Eventually this island starts drifting further away too.