Each individual is different and hacks, programs, apps, or methods will have different results for each person. Here are some evidence-based big-picture ways to improve executive functioning overall:
Exercise: regular exercise has been shown to improve executive functioning.
Mindfulness: Mindfulness practices including meditation and yoga or more formal interventions like Mindfulness-Based Cognitive Therapy can improve executive functioning. However, individuals with a trauma history may have trouble with meditation and should pursue trauma-informed practices.
Mental exercise: While brain games may have some benefits, the best mental exercise is learning new things.
Medication: ADHD medications have been proven to aid with executive function. There is also a worldwide shortage of many of these medications. If you are interested in medication, consult with your prescriber.
Techniques: Not all of these will be appealing to you. Find a couple that sound like they might work and give them a try.
Peer support: There are individuals who work as peer support either with agencies or independently. They can provide some of the below services.
Body doubling: Many people with ADHD find it helpful to have another person with them as an anchor to help them attend to a task.
Accountability partner: Like body doubling it relies on another person, but in this case, it’s simply a person who checks in and asks about a specific task.
Time blocking: Time blocking is just what it sounds like scheduling blocks of time devoted to specific tasks. Not everyone does full-time blocking, which is essentially making a calendar and to-do list in one.
Pomodoro: A time management technique in using 25-minute work sessions with 5-minute breaks.
Visual timers: visually marking a countdown can aid those who have difficulty with a sense of time. These can be in the form of physical timers or apps.
Environmental modification: Simplicity can aid in reducing visual overwhelm, especially in the work area. Reducing clutter is a way to achieve this.
Affirmations: People with executive function issues including those with ADHD experience more negative feedback as children and possibly as adults. Affirmations can rewire the brain and increase self-concept and confidence. One can create their own affirmations or use ones found online. It’s important that the affirmations feel authentic to you.
Rewards: Some people find it motivating to set a reward for themselves at the completion or at some stage of completion of a task. Rewards should be something special and not something necessary like breaks, rest, food, or drink—but fancy food and drink might make a nice reward.
This is a great article from ADDitude Magazine on activities that can improve specific weak executive functions. https://www.additudemag.com/how-to-improve-executive-function-adhd/
Technology
Remember the milk: Creates tasks and sub-tasks with due dates. Map feature for errands. Free with in-app purchases.
Due - Reminders and Timers: Reminders and timers! IOS (Apple) Only. $7.99
Brain Focus: Time management app that helps if you spend too much time on your phone especially. Android Only. Free with in-app purchases.
Clear Todos: Minimalistic designed app for to-dos. $4.99
Todoist: Time blocking app. Free with in-app purchases.
Productive - Habit Tracker: Helps to establish new habits. Free with in-app purchases.
Insight Timer: Meditation and sleep app. Free with in-app purchases.