How do I get a job in Miami?

Hello, I am a British citizen thinking of staying in Miami for a while, for around 6 months as i have been there before and love it! I have been researching Miami and i believe i can stay in Miami for up to 90 days through the Visa waiver programme. But i have been looking at renting an apartment and it seems hard to find somewhere to rent for just 3 months! I would preferably like to go to Miami for 6 months or more and get a job but i need some clarification, do i need to be sponsored by a employer before i can get a working visa? I have been trying to look for jobs over there but reading reviews it seems i am unlikely to get sponsored as it is expensive for the employers! Does anyone know any businesses in Miami which sponsor people? I have tones of experience in customer service, Housing and am bilingual (French). If it is unlikely that i will be able to get a working visa does anyone know any trust worthy companies who do rentals for 3 months? Any help would be greatly appreciated! Thank you, Nil