I am currently working as a Content Writer at a Website Development Firm in Bangalore. I want to upgrade my skills in Technical & E-commerce Content Writing. Can anybody suggest me the right option for learning?

For technical content writing, you should read the tech blogs and news daily to get an idea of the current trends. You can elaborate those points with the help of your writing skills. For improving your e-commerce writing, you can go through various blogs that write e-commerce content. Also, you should first understand the users need and how the user will get benefited from your blog to gain more traffic

Try to read some books on advertising and Communication first. Then try to identify the difference of user behaviour for online and offline buyers. If you can understand the trigger what insist a buyer to press the buy now button, you are done. But the bad news is, you have to find the trigger for each project separately. 

If you want to improve your skills then read more content from websites like scoopwhoop, techcrunch, Yourstory, enterpreneur, kissmetricshq, Neil Patel etc.

This will going to improve your way of writing and add more value and trust to your writing.

Moreover, you can also learn seo writing as many internet based companies are looking for writers who know SEO, especially On page seo.

For E-commerce content writing you need to write information about the product attached to it.

For technical writing you have to do research about different aspects and then go for copy writing.

as for as learning is concern, you will learn new things each day.
one of the best article site is "ezine article" you can get an idea from the article availble on this site.

cheers!!