Writers' Lab: List of Common Mistakes

As I was proofreading my thesis, I made a list of the most common errors that I encountered in my own writing.

Creating a list of your own errors gives you some insights in your writing, areas of improvement and can help you spend some more time and effort on eliminating these errors.

I'm not sure if these are typical mistakes for a native Dutch speaker, or if most writers run into them - and I'd appreciate if you'd give your opinions on that.

For those of you who are proofreading your thesis or a research paper, you might like to pay a little additional attention to the following points:

1. Tenses

I need give my writings an additional round of proofreading, as I tend to shift seamlessly from past to present tense.
Even though I'm still confused as to whether I should describe my experiments in present or past tense, I now at least try to stick to a tense of my choice.

2. Singular versus Plural

When the subject of a sentence gets a little long (as often in academic writing), I lose focus of the subject and often make mistakes against the proper use of singular or plural.
Upon proofreading, I look for the verb and subject and check if they correspond in the proper way.

3. Typos

The typical ones: "strenght", as well as some more obscure typos that make it barely impossible to figure out what I actually meant. If the meaning of the typo is completely unknown, it might help to check which letters on the keyboard are close to the ones in the weird word; you might find out in that way what you actually wanted to type.

4. Prepositions

An error more common amongst non-native writers, I would think, the correct use of the prepositions is a difficult task for me. When in doubt, I simply look it up in a dictionary or online.

What are your most common errors in writing? Are these errors familiar to you, or are these typical for Dutch native speakers?