Expand menu and dock bars

System preferences > Accessibility > Display

... has a selection for menubar size {default, large},

-- but on my less-than-Retina display, it does not seem to make a discernible difference.

You could also experiment with using Zoom to give you a loupe (magnifier) over the area around the mouse.

The Dock size can be increased by tapping the little Apple at the top left of your screen, choosing System Preference, then Dock and Menu Bar. The Menu Bar itself can't be enlarged as far as I'm aware.

The menu bar cannot be changed; however, you can add a lot of apps or files to the dock and have them magnify when you mouse over it - I've got a few in mine: