When I grow up ,on the one hand ,I should study lots of things about sponts, On the other hand ,I must speak fluent English,mustn’t I?
有点别扭。建议整句改成“When I grow up I will study lots of things about sports as well as try my best in learning English.”
Anyuay, English is necessary for me . I should study it (it去掉) hard . One day ,（逗号去掉）I will speak English as well as Chinese , I believe!
最后一句我明白你的意思“我想让英文和中文一样好”。但是容易误解为“我想像中国人说英文那样好。”= =
所以不要怕罗嗦，改成One day I will speak English as well as I can speak Chinese.
而那句I believe放在那里有点累赘。

Of course (改为however), I also have difficulty learning English , I think the most serious one is I always forget lots of new words（貌似前面已经写过了，做flashcard可以解决） , I always make mistakes in spelling the(the去掉) new words . my（大写） English teacher said I should review the（去掉） new vocabularies in time , It’s amazing how much this helped . It helps（过去时） me remember more words .My English achievement（改为My achievements in English） is improved（用词不当。Achievement是成就。不能用improve来修饰） little by little. 　 小荷作文网 ......
Now, I find（have found） that studying English is a part of my life, it opens up my eyes to the outside world（最好用the world outside） .People who know (第三人称单数) about me know（同上） that I want to be a sports reporter especially basketball one in NBA.

Then,（改成so） I always forget some of the words I memorized and some of the English grammar. So,I have a good idea ——making flashcards, It helps (过去时helped) a lot , It helps (helped) me memorizing(memorize) the (the 去掉) new vocabularies profoundly（不适合。去掉） and exactly（改为effectivly）. And listening to tapes is a very important thing(thing改成way) to practice someone’s （改为one’s） pronunciation, I tried it and gained good effect (负数). And I think the most useful one（改成way.） is asking (改为to ask) the teacher for help . I am not afraid of communicating (of去掉。改为to communicate) with my English teacher at all . Because she is always ready to answer my questions and she is very patient, I can’t (改为couldn’t)get good grades without her help. 　 小荷作文网 ......

I think studying English not only difficult,but also very interesting.
[这里not only…but句式一般是递进关系的。不仅，而且。所以difficult和interesting有点不符合这层关系。]
When I was young,I know（过去时knew）that English is one of the most important languages in the world.
So I hoped one day I could speak English fluently (这里缺少标点或者连接词) I even thought I would be a translator in the future. 　
All along since（改成ever since更好）,I study（过去时studied） English harder than (插入any) other subjects. Because (建议把because改成since) English isn’t my native language, I can’t practice English at any time.(at any time意思不对了。你想说“不能总练习英语”但听起来就像“任何时候都不能练习英语”)

我实在是懒得看了！
我不愿意去看，抱歉