Tit Dodulas is the mantra I was given for some help with this as I have always had somewhat of an issue with this. This can be seen in someone's natal chart through quite a few different aspects, abundance of mutable signs, or a misplaced Mercury. There are also plenty of transits and just overall stress that can make it difficult to concentrate at times. Having worrying thoughts, trauma, psychic attacks, repressed emotions can sway our attention even when we try our hardest to focus. It is particularly annoying when meditating or during ritual as it's so easy to miscount as well as feeling disrespectful toward the god we are worshipping. I know I'm not the only one who has had to redo a square later on in the day and it can be infuriating.
I'm aware that there are studies showing ADD to just be a lack of control and manageable, which it is, but these same studies show someone playing a video game with extreme attention for hours at a time and do mention that the reason for this is associated with how much pleasure is linked with the task at hand. It exists and most who don't have this in their chart heavily might not understand and believe it to be mental weakness, or even "fun" since it's is also tied to spontaneity. This is insulting to anyone that has to deal with it.
It is best to concentrate this energy on the heart, but also before this cleanliness is needed as this alone can promote thoughts that go astray. The thymus gland when overstimulated can cause this as well and if there is an imbalance between emotion and reason this is another spot to focus on.
ΛΕΩΝ