Everyone has a person to love. And so do I. To me, that person is my mother. This year, she is nearly 40 years old. My mom is very tall. She has a round face, brown eyes and short hair. To my ways of thinking, she is the most beautiful woman in the world. My mom cooks very well and she is very hard-working. She plays badminton well, too. In her free time, she often teaches me maths or surf the Internet. My mom loves me very much. She can sacrifice everything for me. When I have problems, I always confide to my mom. She encourages and consoles me when I am sad or when I get bad marks.. She gives me a present and is very happy when I do good work. There is an unforgetable memory that makes me love my mom much more. That night, I had an illness and I felt so sick that I counldn't even stand. My mom spent a sleepless night to take care of me carefully. She helped me take medicines and fed me gruel. After a night, I felt much more better but my mom was very tired and sleepy. I love my mother very much. I'll try my best to make her happy and always have a smile on her lips.
The passage above is just a correction of grammatical points. You have a really wide range of vocabularies and use them very well. I see lots of linking words as well as advanced-level words. But if I were you, I would write it like this:
In everyone's soul, there always is an image of a person whom they love most. And in mine, that image is of my mother's. This year, she's nearly 40 years old. My mother is tall, pretty with a round face and brown hair. To my ways of thinking, she is the most beautiful woman in the world. My mother cooks really well and always takes responsibilities for her work. Especially, she plays badminton very well, which comes as a surprise to many people, even me. I love my mother as she can sacrifice anything for me. She always shares with me the problems in life, at school and encourages me whenever I have bad marks or any sorrow. And when I achieve anything in my studying, she always prepares a present for me. There is unforgettable moment between me and my mother. One night, I had an illness and felt too sick to stand. My mother spent a sleepless night to take care of me. And when I was better, I asked my mother if she was tired. She said "No". At that time, I realised, mothers will never feel tired when taking care of their children. I love her so much and I'll try my best to make her happy and always keep the smiles on her face!!!
Because at some points, you use high-level words, and at others, you use simple words. If the level is equal in the whole passage, it's much better and shows your level. This will make your writing interesting in other examiners' eyes.