Some other things to keep in mind:
If you choose a block scale ending with "5", it's harder to position blocks perfectly when you have to move them halfway. That is, there's no scale or grid size of .025, or .075, or .125, etc. Don't pick a scale ending in 5 until you're doing finishing touches, and things will go smoother.
I believe I understand what the different grid settings do: Global grid uses a single 3D coordinate system to snap parts. Local grid uses a separate coordinate system for each part--which should match the global grid in most cases, except when you have a part that's placed at a non-integer coordinate, or with snapping turned off. Block middle is fairly obvious--it will only snap to the centroid (I think) of a block face. I've never used the No Snap/No Grid one because that's only for philistines with no sense of order.
I think people are giving some not-so-safe advice when they say "turn off safe mode and delete all blocks except one", under the assumption that whatever block is left will automatically become the root block. THIS IS NOT THE CASE. It will *sometimes* work--I think if you have a simpler ship, the system can figure out a replacement--but I destroyed my first big, time-consuming build by turning off safe mode and destroying stuff, even though I left blocks behind.
Maybe this was obvious to everyone else, but it wasn't to me: when you've selected your paint color, you can either click on individual parts to paint them, or you can click and hold down and move your mouse over multiple parts, and each will get painted. Sometimes it looks like the textures double-up for a bit, but it sorts itself out after a second or two.
