I was also wondering if you guys use any tools? I use google docs to write down names of all people I've attacked and remove names from the list when successfully plundered. That lets me use it in another browser tab/window so it's not annoying to switch back and forth.
There's a built-in timer plugin for Linux Mint, pretty spartan but it works well.
Have it set to every 25 min to alert me with that, then I click re-run timer and go check. That's why 25 min. 5 min to check players, 20 min intervals.
That way I don't have to reset the timer or anything, just a simple click on re-run. Very quick and easy. Windows users can use free countdown timer program (free-countdown-timer.com) which has more features but works similarly - a popup comes on screen (or a sound) when time is up. I've used that when I was on windows, it's great.
Another cool feature of the timer being integrated into the OS is that I have it in my system tray - two timers actually. One for plundering, one to remind me to collect on time. That's why it says collect collect collect - to make it wider than the other one so I don't get them confused.
I have great success using this system. I attack about 50 players daily and I almost never fail to get the list down to 5 players or less. That means I plunder average of 45 people a day or more. FPs and goods add up real quick.
I don't know why so many look down on plundering, it's a legitimate game mechanic that can reap tremendous benefits for you.
And if you think it's cold - try Grepolis. There you can actually have your city wiped off the map even if you've spent $100 on it. At least here plundering is really just an inconvenience.