As far as the above question is concerned, according to Baker (2014), the most important factors in raising a bilingual child are as follows.
1.Making bilingual children’s language development a pleasure, a positive and enjoyable experience and continuous encouragement of children’s attitude toward their two languages and their motivation to extend their two languages.
This factor matches my experience although I learned English as a foreign language in Chinese mainland. When I began to learn English, my parents and English teachers seldom corrected my grammar errors in my English expression whether at home or in classrooms, instead they often gave me satisfied and encouraging smiles, small praises, which provided a positive atmosphere for my early English learning. What’s more, my family told me proudly that I had linguistic intelligence and suggested me to be an interpreter in the future if possible, which encouraged me greatly to learn both English and Chinese well and motivated me to be very much interested in western culture. Therefore I could always get the highest marks in English examinations with ease at school.
Things are different with a number of my classmates. In their English learning process, their parents frequently laughed at their non-standard pronunciation, strange intonation or stuttering in speaking at home and teachers repeated corrected their grammar errors and talked a lot about how to use language rules in classroom; the result was that this group of children became more hesitated in speaking English and lost confidence in language learning, some even believed that they themselves had low linguistic intelligence and gave up learning English only if it permitted. And it was often the case that these people got comparatively low marks in English exams although they spent much time in it with efforts after class.
2.Adequate exposure to both languages. This factor matches the experience of me as an EFL student. At the first stage I was exposed to the English language two hours a day but I could not communicate in English after five years because of the under-exposure. At the second stage I had received English immersion education as an English major in the Chinese mainland for eight years during which time my English proficiency gradually developed. I could listen to middle-leveled English radio programs, talk with English speakers on ordinary topics, read English materials of middle level and write English articles to express my ideas. And at the third stage, I went to Sydney to accept TOSEL training and Los Angeles discipline management in universities with home stay for two months respectively. During these days abroad I was totally exposed to the English environment: people I met, mass media I used, words I saw and read and culture I encountered, I could feel that I thought in English rather than my native language Chinese. This experience helped me a lot to use English like a native English speaker although there is still be a gap between my English and native English. And this is the main reason for choosing UK to continue my PhD study as I want to expose to English in order to develop more native language proficiency.
3.Encouraging use of the minority language. This factor has two sides and seems relevant to my friend and relative’s experience. 
Josh, one friend of mine is an American teacher teaching oral English in our university; he has lived in China for eight years with his wife and three children. Theoretically speaking, their children could be bilingualism but all of the three children could not communicate in Chinese freely and fluently. Why does this occur? It is because of overwhelming use of the minority language. Firstly, it is closely related to the attitude toward the minority language. In this case, English is the minority language. In order to maintain the dominant status of English, their native language, they teaches their children school courses in English at home without sending them to Chinese schools. Secondly, the environment outside their home doesn’t provide them enough opportunities to use the majority language Chinese because in most cases Chinese people speak English with them regarding it as a good chance to practice their oral English when they meet them. Thirdly it might because  the parents don’t care the children grow up bilingually or not. Otherwise if they went to Chinese schools, their Chinese proficiency would have been greatly developed.
An Pei, my cousin, is an ABC (American-Born Chinese). He has been successfully developed into a bilingual child as he was sent to Chinese school to learn Chinese and Chinese culture a few times every week while he went to American kindergarten. Moreover, his family encouraged use of Chinese as family members don’t think they speak native English and are afraid of not setting correct language examples for him. 
4.The language that surrounds language. This factor also matches my experience to develop my daughter’s bilingual proficiency. I decided to make her bilingual when she was born in 2012 in China. Since her birth, I have tried my utmost to create an English environment for her, playing native English songs, providing her appropriate children’s English books, talking with her in English, letting her watch English cartoons and making English speaking friends. Before she went to the kindergarten, my efforts made achievement because she could understand simple sentences and do simple communication in English. However since she went to Chinese schools, her English develops very slowly because of under-exposure to the minority language. But I am still making every effort to maximizing the soil of English condition and waiting for the growth of her English proficiency.