What are the topics I can start my blog with ?
The easiest way to answer this is to advise that you stick with what you know. Sure, you can blog about anything you want as that it is the beauty of blogging, but the best way to connect with people that come across your blog is to feed them what they want to know. You won't be able to do that if you aren't blogging about what you're passionate about. You won't be able to do that if you aren't talking about topics that showcase a level of knowledge that is above other people that may be blogging about the same thing.
There's no question, that conventional wisdom and advice on this question is to blog about what you love, where your passion is and what is going to keep you engaged in blogging over the long, insightful and fulfilling journey in blogging.