Don't be homeless. As in, don't think or act like a homeless bum. It is possible to be homeless strictly in the sense that you don't possess a fixed home or accommodation arrangement, but don't be homeless in every other association: don't sit in front of shops in rags begging for money to buy alcohol, etc. Don't look homeless, don't think like a homeless person. Have clean, dark clothes. If you ever go to a hostel or any cheap accommodation, never, ever mention you're homeless, otherwise they'll never book you because homeless people tend to be disgusting AND thieves who don't give a fuck or are too stupid to care if they get caught. Why be homeless in one place? Travel, hitchhike and find means to go to nicer places. Don't stay in one place living in a cardboard box. Look into volunteering and live in accommodation. If you're really serious and not a retard, consider emailing hostels asking if they need volunteers. Quite often they do need someone to do a few hours in exchange of a bed and facilities. Then apply for the first job that's decent and pays something. You also got an address now, so making a bank account or any sort of service needing an address is possible. If you work full time, for three months let's say, you'll have all of your income - stuff like phone bill and food left over, meaning you can move on and actually either rent and live settled life or travel further.
Every time I read some retard hoping to live in a cardboard box on 4chan I really want to remind them that they'd rather assume sort of a nomadic, travelling life with possibility for actually seeing the world and doing interesting things, rather than being a retarded fuck up begging for coins to buy a drink before it gets too late and shops get closed for the night... Chances are if you couldn't figure out that there might even be a possibility for another way you're just a larper daydreaming or a legit retard.
All the best.