[Jeff Hinkle]

Couple ways:
If you just need an inside border, apply the Stroke effect set to Inside. adjust color and thickness to taste.

If you need a separate rectangle, make a selection from your original rectangle, choose Select>Modify>Contract and set the Contract By value to how thick you want the border. You now have a proportional selection from your rectangle.

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It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Lots of approaches. Here’s one:

First, forget Quick Select, Magic Wand, and the like. You’ve got a nice hard-edged shell, make your selection with the Pen tool. Once you have your selection, make a new layer, fill with your “car” color and experiment with blending modes like Color.

If you’re wanting to do the highlights with effects, you can probably get something close with Bevel set to (approximately)100 Depth, 135 Size, 5 Soften, 90 Angle, 70 Altitude, and the “Ring” or “Double Ring” Gloss Contour.

That said, studying images of car reflections and making them by hand on a separate layer will most likely give better results and more control.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Composition>Composition Settings and change Starting Timecode to 00

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Organize your brushes in a way that makes sense to you and save them out as collections, then just load the collection(s) you need for your current project.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

If I understand what you’re asking: put your new layer above the lever with the locked transparency (which need not be locked for this to work). Opt/Alt-click between the two layers; your cursor will change to a square with a downward arrow and your top layer will gain a small down arrow next to its thumbnail. Now any painting you do in that top layer will only show where you have pixels in the lower layer.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

I’ll agree with Walter on this one (FWIW). Tilt and pressure, while nice, really only come into play with digital fine arts. If you’re only doing roto work and maybe some Photoshop editing, the lower pressure sensitivity and lack of tilt shouldn’t be a factor. Go for real estate. You’ll be happy to have the room and won’t miss the tilt.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

When you say “rendering out,” do you mean in your final output render or just how it’s displaying within After Effects? Or both?

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

From Adobe Help:

In a sequence, select the clips you want in the composition.
Right-click any of the selected clips.
Select Replace With After Effects Composition.

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It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

Like Joseph said, that kind of shortcut assignment is handled in the mouse software, not After Effects. You can usually (depending on the mouse) specify which application will treat “1” as “undo.” So, for example, you could set “1” to be “undo” in AE and be “brush tool” in Photoshop, if you were so inclined.

—
It is easier to destroy than to create.
More fun, too.

[Jeff Hinkle]

I guess that depends on exactly what you’re expecting by “clean.” How are your strokes not-clean? Most of the brush presets in Photoshop should give you decently smooth lines with no tweaking. Can you post a screen shot of the result you’re getting that you’re not happy with?

—
It is easier to destroy than to create.
More fun, too.