what is the most convenient way in applying for Chinese Visa? I NEED HELP.....

I am so confused,what is the easiest way that I can do to have a Chinese Visa. I have the requirements including the bank account,round trip ticket coming from HK,booked hotel,but lack of ITR since im a private duty nurse. Do i still need to comply on it ITR or COE?

Or should I get an authorized travel agency and avail their promos?How can I contact them? How does it work to receive a confirmed invitation from them?via snail mail or print it through email?

Then I'm also thinking if my american BF with business F holder has the authority to provide me an invitation letter to visit him or sponsoring me? He has a company based in China, and a property too. What are the requirements needed or steps that we can do so that I can get one is the most convenient way??? I BADLY NEEDED YOUR ADVISE. HOPE TO HEAR FROM YOU SOON.

THANK YOU.. (^_^)