I tend to put sentences into google in order to verify that the structure / grammar / spelling of my writing has been used before. This makes writing longs posts very tedious and annoying, but I'm way to afraid to make any mistakes. Most of the time I end up deleting the whole post, just to be done with it. I wish there were more people like you who don't look down on people with poor english skills.
Anyhow, can anyone recommend a book or some articles on how to improve writing skills, especially of technical nature ?
Check out the posts by Gayle Lakkmann on quora[0] related to common English mistakes (you might have to register, but it sounds like almost exactly what you are looking for). It is focused a bit more on mistakes common to those from India, but it is worth checking out. Your English is very good, and I have no trouble following your sentences. Through your use of commas, your writing actually "flows" better than many native writers whose work I read.
Also, I apologize profusely for some of our ridiculous grammatical rules. I'm a native speaker, so I don't think much of it, but I'm amazed at how poor some of the "rules" are.
Anyhow, can anyone recommend a book or some articles on how to improve writing skills, especially of technical nature ?