One of the challenges of ADHD is getting yourself to do The Thing. The Thing could be relatively simple, like returning a phone call or paying a bill, or a more complicated project that you just cannot get yourself to start.
I will start with an obligatory disclaimer that what I am about to suggest works for me (sometimes), but I cannot promise that it will work for you. However, if you are having trouble crossing The Thing off of your to-do list, it might be worth trying.

There is a quote by Douglas Adams: “There is an art to flying, or rather a knack. The knack lies in learning how to throw yourself at the ground and miss.”
For me, the key to doing The Thing is to throw myself at not doing The Thing and missing. In other words, if The Thing is just not happening, I make the conscious decision to not do it. Did I set aside time to write an article and nothing is coming? That’s okay, I just won’t work on it today. Most of the time, that gets me out of my own way, and I can accomplish the task.
Sometimes the sense of urgency that comes from feeling like I need to do something right now becomes a mental block, and it is just not going to happen. As soon as my brain knows it is okay to let that expectation go, I can do The Thing!
The irony is, this only works if you are completely and 100% okay with The Thing not happening. Once in a while, removing the expectation just gives me a sense of relief, and The Thing still does not happen. Besides, if you know you are tricking yourself, it will not work. So, this trick only works on things that can be put off without blowing up your life.
For Things that absolutely cannot be put off, having a friend ask you to do The Thing as a favor to them can help – your brain might not be willing to do The Thing for you, but it will do The Thing for someone else.
I hope these tips can help someone who needs to do A Thing today. If that person is you, would you please take care of it? As a favor to me?