One of the most useful things you can do with text editing keyboard shortcuts is selecting bits of text. It speeds things along a great deal when writing.
Select one character at a time. – Shift+Left or Right Arrow
Select one line at a time. – Shift+Up or Down Arrow Keys
Select one word with each arrow press. – Shift+Ctrl+Left or Right Arrow
Select current paragraph. – Shift+Ctrl+Up or Down Arrow
Select text between the cursor and the end of the current line. – Shift+Home
Select text between the cursor and the end of the current line. – Shift+End
Select all text. – Ctrl+A