I start with a similar shape for the top part of the sink
Extrude extrude extrude scale extrude etc.
I detached and hid the top surface. I cylindrically mapped the sides all together but then deleted two of them.
I copied the side I had left and rotated it 180 degrees.
I did this so that both halves would share the same UVs so I could save space on my texture map
(since I figured I'd be OK with both sides having identical texture.)
I combine the surfaces.
I weld all my verts and grab all the edges and smooth them again-- the seam would have had hard edges otherwise.
