I am no ASP expert so cannot really help with topic choice. However, I have been a full time writer for more than 20 years now and can safely say that your best option is to choose the subject you know most about and are most comfortable talking about, especially for your first tutorial. That way you are likely to enjoy writing it, and if you enjoy writing then people are more likely to enjoy reading it.
Good luck!
happygeek
veganarchist
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You can start with lieral control as well because many people dont know how to embed HTML in ASP.NET which sometimes becomes necessary.
muze
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