Shyflower is write – if your language isn't good, people are not going to trust the accuracy of your content, and you won't get a following. That's particularly true if you're targeting a serious, technical audience. If you feel that you can come up with worthwhile content and can write it in an interesting and engaging way but are struggling with the mechanical writing in terms of spelling, punctuation and grammar, my tip would be to try to find a 'writing buddy'. That's someone who can help you with those aspects of writing – they don't need to be great wordsmiths themselves, just to have an eye for accuracy.
Two, would my all tutorials have to bee advanced, or can they be aim at beginners for the time being. Also is it a problem that the same tutorial (its topic) can be found elsewhere; for example if I wrote a tutorial on horizontal navigation, I am sure that a tutorial on horizontal navigation can be found elsewhere, and that would be better than my tutorial.
Any time you're putting a new site (or even just new pages) onto the internet, you need to ask yourself "what's in it for the readers?" ... and if you can't answer that then you're probably best off not putting that page up there. Because if you, as the author, can't think of any reason why people would want to visit that page rather than the many others out there, then your readers probably won't be able to either. You need to try to find something that you can do better than your competitors, whether it's better content, a more appealling writing style, better site layout and navigation, whatever ... you have to give people a reason to visit your site.