Second empty-mind meditation, it works wonders for one's powers of concentration.
However,
an interesting claim was made in this thread according to which the usual groundwork (meditation, breathwork, visualisation, etc.) wasn't required for doing magic at all. It just occurred to me that it's kinda ironic that so many books on chaos magic to this day follow Peter J. Carroll's lead in prescribing a rigid program of preparatory exercises as an indispensable prerequisite for ritual work when chaos magic is supposed to be so anarchic, punky and against all traditional rules. Many chaotes still consider the Liber MMM syllabus in "Liber Null et Psychonaut" (which takes about two years to complete) a mandatory requirement for successful magic.
Chaos magic authors have turned the dreaded 'lust for results' into a bugbear to the point where it has become a self-fulfilling prophecy, as if one stray thought was guaranteed to ruin your entire operation; one could even claim that it has become a self-sabotaging superstition, the way practitioners turn themselves into knots to avoid anticipating success.
Empty-mind meditation is difficult but a major benefit is that you'll learn not to dwell on a thought after it has interrupted a certain period of stillness. 'Getting back into the groove' (without beating yourself up for your inattentiveness) will become easier after that. Rigorous mental discipline has never worked for me, it was always "Mustn't think of… shit, too late!", dispassionate witnessing is much less disruptive.
The thread referred to above emphasises immersion as opposed to mental discipline. One way to make a ritual a more immersive experience is create a dramatic and impressive one; what works for me personally, however, is meditation as a way to set a ritual apart from everyday life and clear my own headspace before it. I'll get completely lost in the ritual's words and gestures if they're sufficiently expressive, so the immersion approach has much going for it as well.
As far as 'lust for results' is concerned, today I see rituals as necessary interventions that bring closure to a desire instead of kindling it even more: "It's been taken care of. It's in the works. Now I can stop worrying, what a relief!" This also means that now my focus is more on finishing the task before me and less on the expected fruit of my ritualist labours. After all, a desire won't go away completely once the ritual is over but it will be much less pressing, at least that's the way it is for me.
