Forget what you've been told about parking yourself cross-legged for twenty minutes and aiming for a "blank mind." That sentence alone was designed by someone whose brain has only a handful of tabs open at once, meditate definition bible.
The ADHD brain runs on dopamine and novelty and and a stream of sensory information, so the opposite of those things (quiet, hush, repetition) when asked of us, would in most people cause them to feel like something's wrong with them, like everyone else would; but also feel like an immense failure. Which, again, does not ever come from willpower — it comes from a mismatched approach. Start with two minutes.
Don't reach for ten minutes.
Actually start trying for two; which, in the first 30 seconds of which, you are going to lose it in some kind of awesome way anyway; so with all due respect, the less runway you have when it first takes off, the less time it has to pick up too much speed,and you can bring it back! Success is simply returning,and this is your entire rep. By doing the rep for 50 occasions throughout two minutes,you would most certainly generate a stronger attention muscle than someone who just remained still for twenty minutes on the floor —totally unaware of everything.
Movement works wonders; walking meditation, dancing, even wandering the house; or any kind of movement while working on mindfulness... Any of it counts! Consider pacing the house or the room with something to hold or touch and just focus on your breath when it isn't a good situation at all,if anyone in the world were to witness your behavior! Surprisingly enough... "clean the kitchen" meditation (water running, hands in motion and mind in its body) is often times how the most present and intelligent minds actually find bliss with meditation instead of a perfectly poised, straight-out-of-a-yoga-magazine, meditative bliss pose.
Sound can be another savior where complete quiet becomes hard to sit with in an ADHD brain. Listen to your favorite meditation recordings, ambient soundscapes, or even just the sound of the clocks ticking in your room and your brain will do the rest by locking onto whatever thing it's listening to!
Placement of this meditation session within your daily schedule matters too... If you have prescription medication that you take at some point daily then this is frequently a much better time than right when you wake up — when your brain is far from switched on.