It’s easy to become overexposed to a stock without realizing it. I made this mistake while averaging down on Yes Bank and never really thought about concentration risk. 
Quoting @nithin 's tweet today:
For most people, buying a broad basket of stocks or ETFs is a better investment strategy than picking specific sectors and building concentrated stock portfolios. For example, over the last 5 years, the Nifty IT index fell by 8%, while TCS dropped by about 40%.
By the way, we are working on a new Kite Nudge that will alert you when you are placing an order, if your exposure to a single sector exceeds X%