This Worldwide Community is not an official SGI site
Well, maybe try putting up a yellow sticky post-it note on the wall that says Nam myoho renge kyo.
I sometimes, in my opinion by the way, think there's no such thing as a quality daimoku. It's NOT technique. It's what you're chanting for. There have been many times where I simply blank out even in front of my gohonzon and I'm just chanting & letting my voice energizing me. I sometimes imagine myself as if on a surfboard concentrating on keeping my balance, 'feeling' the wave motions and the power of the water take me, and I'm accelerating. OR even on a rocket ship. When I chant that way, I feel energized as my voice naturally just picks up in rhythm, cadence, and volume. Even at times just whispering gongyo with determination I feel very energized afterwards.
Do you do gongyo? Most times I've discovered that helps power my chanting. Even the most 'timid' or even lackluster daimoku I've chanted has actually helped me go through some really rough times. When I used to 'grieve' or mourn the death of my father (and my mother), just the chanting itself helped to soothe the heart no matter how awful I sounded through the tears & choking.
I think in the end a 'quality daimoku' depends upon what you are chanting for and how it feels afterwards if you feel energized or at peace in some way. Because of the 10 worlds, whatever life condition you are in when sit in front of the Gohonzon or your wall in this case, tap into your 'determination', your single-mindedness to get through and push through that 'wall' or block that seems to distract you. It's NOT the wall you're chanting to, it's what you are accessing or tapping into the inner-most core of your life that is the Buddha.
When I chant in my car, the engine and the flow of traffic at times seems to distract me from chanting but I use my voice, sometimes just seeming to block everything else but making sure I have complete control of the car, staying alert, and 'imagining' that the world of the Gohonzon is all around me. Buddhahood is in that pedestrian and I'm alert & ready to stop or slow down if for some reason he unknowling steps out into the street. Buddhahood is in the driver who irritatedly passes me and cuts me off in a no-traffic situation, overspeeding because they're in too much of a hurry. YOU are the BUDDHA. IN your little room, in front of your blank wall, the cosmic magnitude of what you are about to do, to change your life and the vector of your destiny could very well change the world when you summon the vast life condition of the universe through your daimoku.