If you are using blender you can just extrude in one direction scaling it down and at and take last vert's enable proportional editing and move it to top.if youdont understand ill describe it detailed.
Agree with Sumers, the eyes look a bit off. Try extruding the eye faces on Lina directly forwards to check they line up properly. with the mask eyeholes. Also. Do the one with feathers :D
The window frames being an inward extruded detail having nothing between them and space. This makes them appear more as pictures on the wall. Maybe some small exterior pieces for a scene of scale.
i really think you should spend more than 2 minutes on something before posting. Seriously, you extruded a cylinder a couple times and decided that was good enough. (hint: it sucks)
I like to edge-extrude polys over the hi to get the basic geom, then I go over that to improve any edge flow that needs tweaking. Looks great man! nice and chunky
That thing actually doesn't need any baking from hi res model at all neither` all those beveled 3 edge loops. Could all be done by rounding corners shader in Arnold or "bevel' shader in Cycles. Or even just done by placing normal map decals in substance painter and later extruding geometry for lod 01 after the normal map.
Looking at the concept, I think the chin part of the helmet is more... angular. and extrudes a bit further from her face.... Anyhow. I use that hair tutorial before as well. It does pretty good job. What missing chunk you want ?
What kind of printer are you using? I find plastic extruders often don't lay down sharp looking edges due to the thickness of the plastic, so depending on the scale of the print you might not have to worry about smaller rounded edges.
For Maya: Create a CV curve that outlines the path of your laces. Create a Nurbs Circle, and attach it to the end of the curve (Fast way: Hold D+C while dragging it on top of the curve) Go to the Surfaces toolset, open the Surface menu and select Extrude
Model just the seams by themselves as flat geometry on top of a rough block out of the rest of the couch. Start off with a flat plane with no extra divisions. And make sure it smoothly flows around corners. You can extrude along curves if you want.