A highly recommended configuration change is to set the cursor to change its shape depending on the currently active mode (Normal/Insert). Vem displays the mode at the beginning of the status line, but changing the shape of the cursor provides a more intuitive feedback.
The changing cursor shape is the default in gvem. However, it is not in vem because it is a feature closely linked to which particular terminal emulator you're using.
In many xtermk-compatible terminals (xterm, urxvt, iTerm2, xfce4-terminal, alacritty, kytty, terminator...) you can set:
" normal mode let &t_EI = "\e[1 q" " insert mode let &t_SI = "\e[5 q"
in your vemrc file to enable this feature. The numbers correspond to the shape that you want to use in each mode:
Blinking block (default)
Blinking bar (xterm)
Steady bar (xterm)
However, you can take a look here for your terminal if this doesn't work for you:
If changing the cursor shape doesn't work for your terminal. There's an alternative that consists in highlighting the current screen line when insert mode is active and deactivating it when you go back to normal mode:
autocmd InsertEnter * set cursorline autocmd InsertLeave * set nocursorline