Around 12 years ago, as CrossFit was beginning to take off, kettlebell lifting was also becoming very popular. Various organizations were offering certifications, under the umbrella of Russian Kettlebell Certification (RKC). The RKC was in turn headed by a charismatic ex-Spesnatz (Russian special forces) by the name of Pavel Tsatsouline.
Tsatsouline is known for his no-nonsense communication style and his in-depth knowledge of training. I recommend you all take a look at his online articles and interviews, as well as his books.
One of Tsatouline's concepts that I've personally taken to heart and used successfully is that of "Greasing the groove" (bizarre in French). This concept is based on the idea that you can develop your strength by performing certain movements with great frequency. So, instead of doing 5 sets of 10 pull-ups in a single session, you could do 10 sets of 3 pull-ups, but spread out over the whole day.
I won't try to explain the whole concept in my own words because I'll probably spoil it. Instead, you can read an article here.
The fact is, "Grease the Groove" is a great way to improve certain movements, such as push ups and pull ups. Given that we're all stuck at home right now, a simple program based on this method is ideal for making some progress over the next few weeks.
How do you set it up? It's very simple! Do as many push-ups as you can and see how many you can get with good form. If you can't do more than 5, do your push-ups on an elevated surface like a chair or sofa.
I can do 25 push-ups with good form, so I'll use that as my base number. The next step is to set a simple daily goal. Based on my figure of 25, I'm going to set a goal of 5 sets of 10 push-ups, spread throughout the day. This may sound easy enough, but it's 100% the goal! Every set you do should be easy. If you do the reps wrong, it won't work.
Let's not forget that this is not a workout, but an extra "job" to be done during the day.
As with any plan, you have to include a progression. So, after a week, I'll add reps to my total. Either this can be done in sets, so 5 sets of 12. Or I can add sets and do 7 sets of 10. It doesn't matter how you do it, but the total number of repetitions should increase and all sets should be performed easily.