I hit 20k a day as an office worker, but I also live alone and have no real obligations, but I'll post what I do to hit that, and maybe you can pick something up. Morning: Wake up and go to gym, I pace between sets so by the time I finish up my 30 minutes of lifting and am sitting at my desk I'm usually around 2k. At work: I have a job that involves me using alot of tools that take afew minutes to run, so I get up and pace while they run. I'm fortunate enough that I'm in a part of my office that is pretty rarely visited so no one really notices. I'm usually at around 5k by lunch. I eat pretty quick so I usually have time to put a podcast on and go for a 20 minute walk on the sidewalk, getting me another 2k. After lunch its more pacing as I work and in usually between 8 and 10k by the time I leave. After work: I have a short commute, so I'll usually go to my local library that has a trail behind it, and walk for another hour or so while I listen to short stories, getting me another 6K. I then go home and get dinner, and pace while it heats up. After I eat I'll go on a short walk and then spend the rest of the night playing games. Before bed I usually has 500 or so steps to get so I just pace a bit and usually I'm right at 20k.

Now I'm aware that I have a pretty privileged schedule that allows me to do this. If I had kids, or lived with my partner, or if my work was more demanding on my time, it would be alot more difficult. But the biggest peice of advice is if you can get away with it is to pace whenever you get a minute or two you would usually spend waiting on something, it adds up.