Check their Bitcointalk page, website, twitter, telegram and always read their whitepaper. You can read comments in Bitcointalk and somebody will share some interesting news or link about a coin that you find attractive for investing. You don't need to read every single post. You would lose your will, just the important stuff. Filter information.
Thanks for your reply. I would do the same if I were to research on a particular coin. But, how do you find the one. I would like to read about all coin developments and then pick the exciting ones. I am talking about firstly finding such coins. If there is a website/post/thread which only talks coin developments with heading highlighting (reddit is good. But 1 out of 100 posts talk about coin development) that would be great.
eg: "walton has new partnership with xyz".