Macro Tricks
va{V can be used to select the outer block line-wise.
Scrolling
z., zt, zb move "cursor line" into respective position
H, L, M move cursor to respective position
Removing Auto-Inserted Comment Leader
After pressing Enter or ‘o’, use CTRL-U to remove the comment leader. See :help fo-table.
o Automatically insert the current comment leader after hitting 'o' or
'O' in Normal mode. In case comment is unwanted in a specific place
use CTRL-U to quickly delete it. i_CTRL-U