Confused with selecting topics for my blogsite.

As you have mentioned about a topic for your blog site, I would suggest you start with the best of interest that you can present. The topics that you have mentioned shows that you have a clinch in technology and as many are searching for artificial intelligence and android, you can start your blog with this as you will be able to present your better part.

Getting traffic depends upon the subject, content, presentation, and keywords used by you for your article. You can start with the best and then according to the feedback received, you can update your content and articles. Do keep a feedback column where people can provide you a comeback and topics that they would like to be updated.

You can have different topics like student's corner, Fashion, and cosmetics, Food and travels, Technologies, Investments and schemes, Jobs, etc. Every topic needs to be as per the current need and function. You can have a good study on current events and news that is trending and provide a report on it which can get traffic to your blog.

To start a blog is easy. But to sustain it with consistent posts and updates to keep visitors interested and be regular visitors and followers is difficult.
But you have decided"It will be based on technology guides, information and tips. ", and it is a good area and you can write on various sub categories under this umbrella subject. If you are interested, having some academic background or experience in the selected field, then it will not be difficult for you to contribute posts regularly and with latest on the subjects. The area you selected has good scope and gamut. They are current and growing subjects. So there will be demand and search on them.
What were the subjects on which you were writing for others? If they are on the same subjects then you have got some needed experience.
ISC has also many articles and question answers about starting a blog, niche subjects and tips for blog sites get more traffic. You may search the site using suitable key words. Those posts and articles can be of help to you.
The main requirement is you should be able to post regularly and consistently on the subject, get feedback and interaction from readers, make suitable changes gauging the visitors requirements, post quality articles and posts. If the visitors get what the searched for from your blog they will be revisiting and that will help your blog to come higher levels in search.

As you are a member of iSC and had written articles you may be knowing about significance of keywords ,SEO etc.
You also follow other blogs on the same subjects to stay updated and knowing what is current.

To write something creating a blog may appear initially and in the starting phase, you may find interest in sustaining your blog contributing in the regular way but the same diminishes with the time.
If you are really interested to create a heavy traffic in your blog choose the topic in technology, science and other technical areas for which the readers have immense interests.
Your blog should serve as a guide to the aspirants interested to clear any competitive test in Engineering and would like to know the tips to solve the given mathematical problem in a shortest possible time. The problems and hence the solutions are to be dealt with step by step to make it comprehensive for the readers. Your blog should serve as an unique guide to sustain the interest of the readers. Each time you will be dealing with a new coverage and the inputs therein would be of their upmost interest.
Sustainability of the contributions should be the main criterias of your blog. Collect the feed - back of the readers and try to satisfy their sentiments. In that way, you may enhance the traffic in your blogs. If the readers find different postings of their intersts, they would be the regular visitors and in that way, you will arouse their interst.