Marking the Keyboard for screen reader use.

When using a Windows screen reader, mark these keys. F4, F7, F12, Caps Lock, Windows key, down arrow, home, end, and backspace.
System Access, NVDA, and JAWS use the Caps Lock as one of the modifier keys. You can also use the insert, scroll lock and numpad insert, but I find that using the Caps Lock works best for most people. This setup of marking works well for laptops and desktops.
The marking can be done with a braille label maker, plastic dots from places like Maxiaids, or pieces of velcro hooks. Get the kind of velcro which is ready to stick on and use only the hooks, because it’s more tactile than the wool. You can get it at any hardware store, or places like Walmart.
Good typing is essential for a screen reader user. You don’t have to be fast, just accurate. You won’t be able to do anything on a computer until you can type.

Marking a Macintosh keyboard.

Put an indicator on the following keys
Control, up arrow, F5, Tab, Delete, F and J
This will be enough to help you make good use of Voiceover.