I use CTRL for all of the tools - 1, 2, 3, 4, never five. I use keybinds for everything. the people who say they “can’t get used to them” are the people that tried keybinds for 2 minutes and gave up. Seriously, remembering ctrl+2 is easier than remembering what 26+12 is.
I know these keybinds and I use some of them every day.
CTRL + ALT + G - group into a folder
F2 - rename instance
ALT + C - select all the connections of a part (I don’t use this often
you probably know these ones, I use these often too.
CTRL + G - group into model
CTRL + SHIFT + G - union
CTRL + SHIFT + N - negate
CTRL + SHIFT + U - seperate union/negation operation
CTRL + U = ungrop, works for folders too
F - go to part
CTRL+L - local space
I use backspace or delete for instances. I use F5 to playtest. I use shift+f5 to stop.
some plugins I use that actually help a lot are
Studio Build Suite
I use this to resize a large group of parts at once, such as wedges on a roof that are too short.
MaterialFlip
I mainly use this to correct my wood grain mistakes. Pathetic I made any in the first place.
GapFill
Probably the most used plugin for me, usually only when building roads.
Camera Light
This has actually been helpful in most cases.
Resurface
I don’t use this often but when I do it’s usually for aesthetic or whatever I’m doing.
ResizeAlign
I don’t use this one as often over gapfill, but it has different use cases.
Optimization is something I don’t actually pay attention to much, but if I were to then I’d say you could still add details but substitute for textures when they look the same. Having a ton of parts in a small area will lag a user a lot.
I do recommend unioning parts when making vehicles, notably for things like doors if the part count is very high. When making a build, you should union parts that don’t really have collisions that matter as much.
The way I organize my games is using folders of course. I put terrain objects in one folder and the parts in another. Sometimes I’ll have folders like “Buildings” in the “Parts” folder, to organize better.