[kar5pt]

I've been doing mindfulness meditation for around 7 years now (I also have ADD). It helps my focus a bit, but comes with diminished returns over time. I meditate for other reasons but I wouldn't recommend it just for focus. The amount of time and effort it takes isn't worth the marginal benefit to concentration. I still struggle with the same focus problem OP does.

[Pyramus]

YMMV and there will be definitely be people like yourself, but from my own experience and the research I've read, this is exactly what mindfulness meditation is targeted at:

1. The ability to detect the mind wandering off.

2. The ability to re-direct attention.

There are studies showing that neural circuits linked to 1 + 2 are strengthened when doing mindfulness meditation. This benefit is specific to mindfulness meditation, and hasn't been shown for other types of (secular) meditation like transcendental meditation or relaxation exercises.