I busk all the time. Usually make around €15 an hour (though my repertoire only goes up to about an hour, so I do 2 1h sets). In the town I live in busking is very common, so much to the point that I sometimes hate busking in this particular town! Its accepted everywhere in Ireland, but my town is somewhat the Mecca of busking in Ireland. It can pay off really well, but sometimes theres just so much other competition, the standard is really high, people can oft be unfazed by so much music, etc.
Id say really hammer in the tunes that you do know. Know them perfectly, not 85%, or 95%, but 100%. Theres nothing worse than making a mistake when playing in front of a crowd, and it just spiraling out of control until you eventually just stop dead in your tracks, to the disappointment of everyone. Ouch! So awkward! Its the difference between letting your muscles go on auto-pilot to do the magic when youre feeling a bit anxious, and over-thinking what youre doing and just flopping. Id say thats a bit of a no-brainer anyways, but busking really separates the tunes that you truly know how to play and the ones you thought you did. Its ok making a mistake if you can brush over it and carry on, but having one mistake snowball into another is really really really not what you want.
Busk on pedestrian streets. Busking on a street by a busy road is a bad idea, even if its just mild traffic it can be off-putting, out of place and will drown out your sound. Busy pedestrian streets, ideally by some cafes/bars/restaurants, are the best. Perhaps its different in your country so Id say if youre going to busk outside an establishment ask permission first. I dont have to here because all the shopkeepers are so used to it

But like I said the way of the land might be different where youre from. Parks arent bad either but honestly a good busy pedestrian by some restaurants is king busking location.
Give other buskers ample space, and time. You dont want to congest a street too much with different music, and you want to spread out the tips. If there are no legit busking spots about, ask a busker if you can play after them. Agree on a time and come when necessary - dont have someone waiting around for you! Ive been left waiting for up to 20 minutes before, reserving spots for strangers, only for me to give up...
Try to not be repetitive. Like I said earlier, I have about 60 minutes worth of tunes on the accordion, which I play twice. You dont want the locals and shopkeepers getting sick of your music, and of course you dont want to be getting sick of it either. I wouldnt play the same song 3 times in one busking session unless its going REALLY well and youre really feeling it. Variety is the spice of life
Thats about all I can think of. Try not to get frustrated if the tips arent coming in. Sometimes its just like that. One busy Saturday you might make €30, the next busy Saturday at the exact same place you might only make €6... If youve got some skills on your instrument youll find that its pretty consistent, however there are random dud days where it just doesnt work and you have to deal with those.
I really love busking. I love lighting up the streets with my music, entertaining people and adding to the overall ambiance of an area. Its nice just playing music, while watching the world go by... Getting money for it too is of course a very great added bonus!
Heres the list of tunes I play
Katyusha*, Korobushka*, Kalinka*, Ozidanje*, Dark Eyes*, Farewell to Slavianka, Oi ne Chodi Hrtyziu, Susidko, Two Guitars, Misirlou, Cumajle, Jovano Jovanke, a nameless daitschevo from Macedonia, Cacak, Minek a Szoke Ennekem, Sherele*, Hava Nagila, Tanz Yidlekh, Karens Klezmer, nameless honga + nameless freilach*, Varshaver Freilach, Bukuria, Masquerade Waltz*, Where is My Mind (Pixies), La Noyée, Odessa Bulgar
*These tunes seem to be the most liked by people. I dont have a particular favourite tune (though I do really love Sherele) but these ones are definite crowd pleasers! All of them can be found on Youtube, or through the internet if youre looking for sheet music, bar the nameless honga and freilach which I learned by ear from
this video. On a bit of a rant so Ill leave it there. Best of luck!