questioned about Visa Supporting Documents

HI good day, I want to travel to China next year and would like some assistance please. (1) Do I need an invitation letter if im staying at a hotel? (2) I saw online that I need copy of chinese hotel booking as supporting documents, does that mean I have to pay for the hotel first before even getting my L type as proof of accommodation? (3) I also saw I need copy of an outward and return flight ticket booking, does that mean I have to actually purchase tickets before even getting my L type as proof of return or would a flight internary with dates ect. be sufficient? & (4) I want to travel March 2016, is it to early to apply now? I would like to have my L type and tickets ready as im such a planner! Awaiting your response & would be most appreciated. Thank You xoxo