Sanitizing $_POST input

So I have the following code:

‘$fname = ($_POST[‘first_name’]);’

to

‘$fname = esc_attr($_POST[‘first_name’]);’ ??

—————————————————–

$email = $_POST[‘user_email’];

to

$email = esc_url_raw($_POST[‘user_email’]); ??

Is the above correct?
Should I use WordPress sanitize_*() class helper functions or esc_attr()?