We've all heard it a thousand times by now, but the old saying of "fail to plan and you plan to fail" is still as true as ever. And it's just as true for checkpoints as it is for any other part the race. When your getting within a mile or two of the CP, take a few moments to think about what you need and how to best go about getting it. That way you won't find yourself spending 15 minutes in the checkpoint without filling up your water bottles.
99% of the time the folks working the checkpoints are just running enthusiasts who are volunteering their time to help you. Be nice to them and say thank you, even if they might sound a little frazzled after looking after hundreds or even thousands of runners before you.
Every second you spend in a checkpoint is a second longer that you aren't running. Give your self a time limit and don't let yourself stay in there a second longer. As the race goes on and you get tired, you might increase your time limits but make sure you decide how long you'll be in the CP before you get there and never stay longer than planned.
Sitting down at a checkpoint is just asking for trouble, not only will it make you more acutely aware of how tired your legs are but it will also make it 10 times harder to get going again. Sit down only if absolutely necessary, changing socks etc.
Whether you have to show your number or dib your dabber on a terminal, make sure it's the first thing you do when you get to the CP. There's nothing worse than getting a mile down the road and realising that despite spending ten minutes at the last checkpoint you never actually checked in.
When the going gets tough it can be really difficult to make yourself leave the comfort of the checkpoint and get back on the course.
If you find yourself really struggling try to find a person or group of people to leave with and commit to going for half a mile, if you still want to throw in the towel, you can return to the checkpoint and tap out knowing you gave it your all.