Snap to grids
1 studs
0.5 studs
0.25 studs
0.125 studs
In case you need to fix z fighting, use 0 studs. 0 studs in almost any other use case can lead to a lot of misalignments, which are very unsatisfying to look at.
Rotations
90 degrees
45 degrees
22.5 degrees
15 degrees
11.25 degrees
And if you like smaller rotations, 6.125 and 5 are good ones.
Keybinds
CTRL+D is better to use than CTRL+V, because CTRL+V makes the part you pasted go on top of the other one, and it automatically parents to workspace. CTRL+D parents to the part you pasted parent, instead of workspace, and it keeps the same position.
Lets say you wanna copy a part to a bunch of other parts, CTRL+SHIFT+V has got your back.

CTRL+C the part you want. Using CTRL+SHIFT+V, you can paste the same part to a bunch of other parts, like this.

You can use CTRL+L to switch from Global to Local movements. Global makes it where it keeps the same movement rotations regardless of the part’s rotation, while Local makes it so that the movement rotation goes along with the part rotation. If that made sense.
Global

Local

CTRL+1/2/3/4/5 switches between these 5, and is very handy and more efficient.

You can hold ALT to select individual parts in a model without all that tedious work.
You can hold CTRL while scaling a part to scale it from both sides.
These are probably more obvious/unused ones but I’m putting them here just in case.
CTRL+Z to undo
CTRL+Y to redo
CTRL+A to select everything
PGUP (PageUp) /PGDN (PageDown) to align your camera up/down
< > to align your camera left/right
You can also hold CTRL/Shift to select multiple parts.
Plugins
Here’s some great plugins to use that come with many different purposes.
AutoScale Lite
In case you ever use a GUI, this is a great plugin to use. From the description:
“Simple plugin that helps you scale your GUI on all screens! Change Position, Size to Scale/Offset and also add UIAspectRatio constraints with the Ratio property calculated for you!”
Archimedes Two v2.4 / 3.1.6
Whatever version you want to use comes to personal preference. Personally, I enjoy the v2.4 version better, but it’s up to you.
“This plugin allows you to make smooth arcs / circles.” Simple enough, but just because it’s simple doesn’t mean it’s not extremely useful.
Oozledraw Toolbar
A plugin that will help a lot with making tight ropes and curved structures.
Studio Tweaks
A very good plugin that adds a lot of tweaks to studio. One of the most useful features is the automatic part anchor feature in “Instace Defaults”, it will help a lot with building stable structures. Of course there’s more to it, here’s a look at the UI.

Part Counter
In case you’re building something for something and it has a part limit.
Surface Tool
Another simple tool that brings back a very nice feature, the Surface Tool. In case you ever want to add inlets, studs, motors, glue surfaces onto a plastic part for more classic builds or just any other purpose where it fits really.
https://www.roblox.com/library/5070921519/Surface-Tool
ThreeDText 2
A plugin that… well it’s in the name. 3D Text. Useful plugin in case you’re tired of 2d text I suppose.
A few more tips
It’s best to turn off “Join Surfaces” unless you need it. It’s more of an inconvenience than anything.
While you’re at it, turn off collisions too. You don’t have to do those things, but it may be best to turn them off.

If you ever have a locked part, and you just can’t find it in the explorer, remember this button is here to save your heart from having an attack.

That’s really all I want to say really. Hope this helps!