我来自我介绍一下
"来自" means "come from", and “自我”in this place can express"by myself". It is obvious that you would like to express "you will introduce yourself". "来" and “一下”are conversational  style word in this place and do not affect the sentence's meaning.

你们好, 我叫Eric, 我是荷兰人。 我在海牙孔子学院学中文。
Generally speaking，in chinese, the place you do some thing should precede the Predicate and the Object. e.g. I learn chinese in Haiya Kongzi Collage. In chinese, you should say " in Haiya Kongzi Collage" before "learn chinese", so the sentence is "我在海牙孔子学院学中文".

 我<strike>是学</strike>在阿姆斯特丹大学学习人文地理学<strike>的</strike>。
The same as the last sentence, you should say "在阿姆斯特丹大学" before "学习人文地理学" . In this place, “学人文地理”do not the false usage， but I feel “学习”is better.
去年我<strike>是去</strike>到中国旅行<strike>的</strike>，明年我想再去中国<strike>第二次</strike>。
“到中国”emphasise a situation that you have done, while "去中国"emphasise an action that you do. Last year, you have travaled in China, so you'd better to use "到中国" to express you have been to China. In chinese，we often do not use ”第二次“ directly to express "the second time" . We often use other words to express the meaning, e.g. "再"which means again.

我的工作是地理信息系统顾问。
我能教你荷兰语，英语和德语，我想要学习汉语。
The same as english, The Predicate often precede the Object. ”教“ should precede ”你“。“我要学习汉语”is a right expressin. But in Chinese， we feel like to using euphemistic expressions. So “想要would like to'' is better. ”希望hope'' is also a good choice.