I am a bit down at the moment, because despite perfect conditions today, (sun shining and -6°Centigrade) I went out and delivered two of the most miserable, pathetic sets I am ashamed to recall. I earned virtually nothing, which was all I deserved. Let's hope you do not ever play that badly!
However, although the good days can be truly wonderful, remember that although you can make money and have fun through sheer luck from time to time, the only way you can do this consistently is by being really good. Nowadays you have to be a lot better to make money than I was when I started (some thirty years ago). You will only make money consistently if you look good, sound good and feel good. Whenever you see a successful busker with a big crowd, stick around and watch what they are doing, which you can learn from. I was lucky, I got to watch masters like Glynn Nicholas and his idol, Phil Free. (Paul MacNeill was not bad either).
Bad buskers (which is what I was today) do not make money. Nor do they deserve to. There are no excuses for not making money. It means you failed, point. Watch other buskers, get well prepared and read the other busking threads here. Good luck!