Unordered list of some tips and examples:

• In order to drop traffic to-from banned networks or IP addresses, use IP sets in the raw table of netfilter.
• If you want to change a set without disturbing your existing iptables rules, simply swap it with the new set:

  # Create the new set and add the entries to it
  ipset -N new-set ....
  ipset -A new-set ....
  ...
  # Swap the old and new sets
  ipset -W old-set new-set
  # Get rid of the old set, which is now under new-set
  ipset -X new-set