There is a difference between street performing and street playing. In order to be adaptable and durable in the occupation, one should be handy at both. Anyone acting with brashness and no inhibitions can turn it into a street performance, though that is not the only way to go about it. Stand in a public place and shout, it doesn't matter what you are saying, and people will gather around to see what's happening.
I talked to some street clowns in Barcelona and asked them how they gather a crowd. They told me that shouting and mock arguing and fighting is the only thing that works. If you don't have anything worked out you will shortly be ashamed and abandoned, except in the case of extraordinarily talented people. Street "performing" requires an arena-style space of some sort. With or without participation it's an audience-performer energy exchange. After a cycle of about 15-45 minutes the performer is usually finished for a while.
A street "player," however, can go on for hours. He can be much more withdrawn than the performer. It's not necessarily to his advantage for people to gather around him. He's not really intending to amass that sort of energy and may not feel up to being the focal point of it. With his instrument he mainly works to passersby and wants people to notice just enough for appreciation and a coin, but to stay in their flow.
Street players earn money more slowly, but more steadily. They can play in places unsuitable for the street performers. The discreet street player will often be left alone by the police where a street performer would immediately be stopped. There's a lot more tension created when you gather a crowd. More possibility for a happening and quick money, but more risk of conflict from all the sedentaries, especially due to blocking the passages.
Usually street players rely on their practice, technique and endurance while the performers rely on inspiration and more surprising expressions.
Ideally the street "artist" can wave in and out of these different functions fluently. It's better not to beat your brains out trying to do a performance in a bustling workday environment, and a bit of inspired street playing can spontaneously turn into a performance in a strolling leisurely environment. The canned music systems which are unfortunately appearing in European shopping pedestrian malls are more serious impediments to the players than the performers.
A person who sits on the street with an oppressed look on his face and a sign could also be said to be street performing in the most pitiable sense.
I remember a hallucinogenic experience in the hills in northern California where in a pasture a herd of sheep came and surrounded me, striking fear in my heart. Then I thought, "Wait a minute, I'm a man and these are sheep." So I managed to look one sheep in the eye and strike fear in him and then the whole herd took fright of me and retreated to the other side of the hill. Then one sheep turned and looked back at me and caught my eye and created fear in me so then the whole herd returned to surround and threaten me.
It's a bit the same game of confidence vs. insecurity, attraction and repulsion in working an audience, on the street or otherwise. People will watch and admire as long as you exhibit assurance and confidence and they will just as easily mock or abandon you at the first glimpse of doubt and fear. If you hold up a glass of water and talk with clear confidence all will be mesmerized. If you falter and doubt while juggling five objects they'll walk over you and away.
You may have witnessed the phenomena of a street performer sloppily juggling three balls yet managing to entertain and keep a large crowd, while another performer doing much more technically difficult tricks is ineffective abandoned. The important thing is not so much what you are doing, but how you are doing it in the sense of the 'relationship" with the onlookers that you are cultivating while you are doing these things. And also your successes in creating a sense of togetherness amongst the random individuals who have stopped to watch. This is the magic of good street performing, in that it takes random passersby in the sterile business of modern cities and molds them into the unity known as an audience, and bonds them together with common experiences and emotions. Whether people shit on you and abandon you without giving a penny, or stay around to give and also thank you largely depends on the relationship and sense of commitment which you have succeeded in molding with them.
This comes from the skill and discipline behind what you have shown them, and more importantly, the fact that you have entered into relationship with them, tapping into the deep-rooted empathy and inclination towards devotion and sacrifice lying suppressed in human nature.
The true street performer ideally is not just doing his act, but bearing his soul open before the public in full risk of being abandoned and degraded. He doesn't have the protection of a stage and theatre with its aura of reverence and the precommitment of people who have paid and taken their seats, already investing themselves in the exchange.