what is the best way to manage the workforce of a small to medium sized sole entrepreneur biz in the country?

This i ask because i've noticed that in a large number of the most successful businesses, the proprietors are actually harsh, arrogant to and often mistreat their workforce.
Basically, successful businessmen will set ground rules from the onset and will not take flimsy excuses,
On the other hand, when workers are given their space then 'wanacheza na kazi'. And many agree that this is a recipe for failure especially for medium sized businesses.

Is this a secret in managing workforce? And is this a quality to want to cultivate or pretend to have in case you are naturally a soft person?

After High school I worked for a sole proprietor who was like that and after listening to her shouting 4 a few days I got immune to the shouting. We used to call it ringing the bell. @ Mkonomtupu while harshness is one approach, at times it's overdone and other times it's given much attention at the expense of actions that would bring in a return. I know of this business owner who runs the show from basic things like overseeing who seats where in the office to growing the business. But because he has to be involved in every activity and has to shout about everything he forgets his main job which is creating wealth for himself. In my opinion many sole proprietors fail due to multi tasking, and not having clearly defined objectives and if the have they don't persue them as they should.

Unfortunately, this is true. and they will steal from you too

Ditto!

Tried being nice but as bwenye has said, the kenyan workforce feels entitled to do nothing. Probably got it from their parents who left coats in their office seats for lunch.

I don't know of any small businessman who's not suffered from being nice to the workforce. However, I would be very happy to learn how to do it. But for now, wacha the owner shouts at the workers otherwise he will be a statistic of "muone, alikuwa na kabiashara kakakufa"

Its all about the business culture that you promote. If I join a company where ppl work very hard and get promoted on merit, I will try to outperform the best.

A good manager however needs to know how to motivate his staff. Reward and punishment, praise and admonish, set goals, the higher the goals are met, the higher the bonus and rewards.

Create office politics to work in the right direction. Generate conflicts that lead to good performance. I.e., let the employee know that if he outshines the supervisor, the supervisor will be fired. Then, tell the supervisor that the employee has been reporting what the supervisor has been doing. Fix the supervisor by allowing him to steal something from the company and you record it as a point of dismissal but tell him his performance will determine if he goes or not. At that point, Kazi itafanywa mpaka moshi itoke.

Shouting bosses and supervisors are simple idiots who do not know how to manage people for optimum output. In most cases where the boss is harsh, the work being done is usually menial or requires low IQ personnel who have to be herded like cows. The pay is also poor and the company in most cases does not raise enough revenue for expansion and growth. Bosses in such scenarios are also low IQ busy bodies who should not have been in charge of human beings in the first place.

Appraisal, proper pay based on performance, qualified personnel who know what they are supposed to do, etc tends to work better than screaming managers or bosses.

Screaming bosses tend to overwork themselves as they have to show the employees what to do regularly as the employees can not think on their own. That is why Muindi na Mkamba seem to prefer this model. That is why Mkikuyu na mjaruo make a good coalition government.