best way to drain fuel tank

[sannad]

hi everyone!
so my '78 300d has been having issues accelerating and reaching maximum speeds. the plastic inline filter is not anywhere near being half full, so i have a feeling that its not getting enough fuel. i was going to start by cleaning the fuel screen on my tank....
everything i've looked up on line says to just drain the fuel tank, what would be the easiest way to do this???
and then how do i get the screen out?

thanks!
sanna