The flower in your file is a single mesh item. You can use multiple UV maps, but i would just use one UV map for everything. Here's how i would handle the UV'ing for each portion:
- Select the default "texture" UV map and delete it.
- Create a new UV map
- For all of the petals, i would use "Project From View" because they are reasonably planar meshes if viewed indiviudally. Select one complete petal at a time. Orient the camera to look straight at the petal. Pick the tool. Click in 3D viewport. Select those polys in the UV view, and drag them to the side. Repeat until all petals have been mapped in this way.
- For the "twigs", i would use the "UV Peeler". Select one edge along the length of one single twig, then run the tool. Select those polys in UV space and drag them to the side. Repeat for all the twigs.
- Now select all polys in the UV space, assign a selection set and hide them (don't forget this step!!!)
- Now it's up to you if want to unwrap your pistles all together or in seperate unwraps. If unwrapping one by one, you must hide all but the one being unwrapped. After unwrapping I think it will take longer, but you will get better results. If you unwrap one by one, you can select the new uv faces, drag to the side, and then assign to same selection set as earlier steps. Then unhide everything, select a new thistle, invert/hde, and repeat until all is done. The selection set will help you select/hide the mapped polys between each step.
- After all this, unhide everything, and try the Pack UV tool. If that doesn;t work, i suppose you need to do some handwork...
For the painting, i would just use one big texture (2K or maybe even 4K). Assign it to diffuse color, then create an instance of that image map and assign it to the SSS color. Beyond this is all up to your artistic skills (something i do not have, so i won't try to give any advice there!
)
Hope this helps...
shorty