Pure processing speed is difficult to improve upon. Even if you do the brain training programs, those improvements usually do not generalize over into the real world.
However, there are a lot of things that you can control that will impact real-world application.
Many of them are similar to what we work on with executive functioning and ADHD symptoms.
Brain health – How is your diet, exercise, sleep, etc.?
Multi-tasking needs to be taken out of your vocabulary… etc.