Recently, I have came across an article about the importance of reading. It said that reading can help us to expand our knowledge and increase our vocabulary. However, I find that I have difficulties in read books, because there are always some new words and phrases that I don't understand. This makes me feel frustrating and I often give up easily. In addition, I also have problems in writing. I often make mistakes in grammar and spelling, which make my writing look unprofessional. I know that I need to improve my English, but I don't know how to start.

解析：

1.错误：I have came across
改正：I have come across
解析：come across是固定短语，表示“偶然遇到”，不需要加助动词have的过去分词形式。

2.错误：in read books
改正：in reading books
解析：have difficulties in doing sth. 是固定句型，表示“在做某事上有困难”，所以需要用动名词形式reading。

3.错误：This makes me feel frustrating
改正：This makes me feel frustrated
解析：frustrating是形容词，通常用来描述事物令人沮丧的特性，而frustrated是形容词，用来描述人的感受，即“感到沮丧的”。

4.错误：give up easily
改正：give up easily
解析：虽然这个短语本身没有语法错误，但在上下文中，为了表达更强烈的情感，可以在easily前加上too，即give up too easily，表示“太容易放弃了”。

5.错误：which make
改正：which makes
解析：这句话的主语是前面的整个句子（I often make mistakes in grammar and spelling），作为单数概念，所以后面的动词要用单数形式makes。

6.错误：my writing look unprofessional
改正：my writing looks unprofessional
解析：整句话的主语是my writing，作为单数概念，所以动词要用单数形式looks。

7.错误：need to improve my English
改正：need to improve my English（此句无错误，但可添加细节）
解析：虽然此句本身没有语法错误，但为了表达更具体的改进方向，可以添加一些细节，如“need to improve my English in both reading and writing”。

8.错误：but I don't know how to start
改正：but I don't know where to start
解析：在这个语境中，使用“where”比“how”更合适，因为作者是在寻找一个开始的地方或方法，而不是一个过程或步骤。