很高兴听到你想提高你的英语写作技能！以下是一些常见的语法错误，希望对你有帮助：

1. 主谓不一致：确保主语和谓语在人称和数上保持一致。
例如：My brother and I is going to the store.（应该是 My brother and I are going to the store.）

2. 动词时态错误：确保动词时态与上下文一致。
例如：Yesterday, I go to the park.（应该是 Yesterday, I went to the park.）

3. 代词不明确：确保代词的指代清晰明确。
例如：She gave her book to her friend, but she didn't like it.（不清楚“it”指的是什么）

4. 冠词错误：确保使用正确的冠词。
例如：I want to eat apple for breakfast.（应该是 I want to eat an apple for breakfast.）

5. 句子结构混乱：确保句子结构清晰，避免过多的从句和修饰语。
例如：After I finished my homework, which I had been working on for hours, I decided to take a break, but then I remembered that I had to study for a test, so I started studying instead.（可以简化为：After finishing my homework, I studied for the test.）

希望这些提示对你有所帮助！记得在写作时仔细检查语法和拼写，多读一些英语文章也有助于提高你的语言水平。