There’s an vim/evil command that I use often and is named evil-open-below. It’s bound to o in normal state. What it does it starts a new line below the current one, moves the point at the beginning of it and switches to the insert state. Really simple and really useful. Often when writing lisp I wanted to open the new line but stay inside the current expression. Using smartparens it was quite easy to achieve what I wanted. Look at this:

(defun sp-open-below ()

Also it’s a good idea to define it as an evil command so you can use the dot for repeating it:

(evil-define-command sp-open-below-command ()
         :repeat t

And bind it to “M-o”:

(evil-define-key 'normal smartparens-mode-map
         (kbd "M-o") #'sp-open-line-below-sexp-command)

The command in action:

Command in action gif