Add the following to your ~/.screenrc and you'll see a status line down the bottom, showing in inverted text the date, time and system load. More escape codes found in man page link below.

hardstatus alwayslastline
hardstatus string '%{= wb} You are in screen %n @ %H %S %{-}||| %Y-%m-%d %c | %l ' 

caption always # activates window caption
caption string '%{= wk}[ %{k}%H %{k}][%= %{= wk}%?%-Lw%?%{r}(%{r}%n*%f%t%?(%u)%?%{r})%{k}%?%+Lw%?%?%= %{k}][%{b} %d/%m %{k}%c %{k}]' # good looking window bar

bindkey -k k5 prev # F5 for previous window
bindkey -k k6 next # F6 for next window

• http://www.kilobitspersecond.com/2014/02/10/understanding-gnu-screens-hardstatus-strings/
• https://www.gnu.org/software/screen/manual/screen.html#String-Escapes
• https://serverfault.com/questions/377221/how-do-i-know-im-running-inside-a-linux-screen-or-not