We'll see us tomorrow...

While this construction seems sensible to many Germans, it is incorrect. I don't claim to know all the nuances of reflexive pronouns, but can tell you the proper way to express this thought is "We'll see each other tomorrow".

I digged your blog...

irregular past participles can make the most fluent speaker of a foreign language sound like a third grader, even if just for a moment. One of the ones I hear most consistently misused is "digged", as in "we digged ourselves into a hole". "Dug" is the past participle of dig -- "we dug ourselves into a hole".

I'm going to the toilet...

This post is more about usage than grammar and underscores a difference between American and British English. While the use of the word toilet is, in my experience, perfectly normal in the UK, it has taken on an indelicate connotation in American English. As a matter of fact, saying you're going to the toilet is almost vulgar in American English. This usage is encouraged in many non-Americans by cognates prevalent in various European languages, German and French leaping immediately to mind.

Just a heads up for those who might be traveling across the pond. More common and/or polite in American English is to use "bathroom" or, even more politely, "restroom".

I've been writing this blog since 7 months...

Here's another time-related proposition. I often hear native German speakers say "I've been working at ACME since 3 years." The correct proposition in this case is "for", "I've been working at ACME for 3 years.". Use "since" if you're refering to a particular past date. "I've worked at ACME since June of last year." is correct.

Are you reading this blog at that time?

The use of demonstrative pronouns can be tricky. If you want to refer to something that is current or happening now, use "this", not "that". I often hear Germans say (in meetings for instance) things like "We don't need to do anything at that time". Since they're refering to right now, they should say "We don't need to do anything at this time."

"At that time" is used to refer to a period of time other than the present. For example "I didn't like high school, but at that time I had no choice but to go." or "We'll go to France tomorrow and at that time will assess our options."

I wonder if persons like this blog...

While there are valid uses of the word "persons", most often one expresses the idea of more than a single person with the word "people". Today when I was signing the contract for electricity in my apartment, the very kind represenatitive asked me: "How many persons live in your flat?". While in no way ambiguous, this usage sounds odd.

Much more natural sounding would have been "How many people live in your flat?".

Did you make a good experience?

German speakers often have trouble determining when to use "to do" and when to use "to make", as a single verb is used for both these meanings in German (and Spanish, Portuguese and I'm sure many other languages). Since these verbs are so common and used in many contexts, there's no reliable usage rule that I can discern. I'll therefore call specific examples of misuse that I hear regularly.

Today, I'd like to talk about "making" an experience, as in "I have made good experiences with that approach in the past." This use of "to make" is wrong! One "has" (to have) experiences. The example sentence should have read "I have had good experiences with that approach in the past." I hope you have had a good experience with this post!