In today's ecosystem, verification of identity is no longer applicable just to the user; extending to microservices, cloud providers, IoT devices and many other emerging systems as well. 81% of discovered breaches are due to broken authentication, indicate it as a prevalent issue. Developers are generally aware of different authentication methods used for secure interaction between these entities, but most often lose context on best practices. In this context, we talk about popular authentication schemes like SAML, OAuth, token, magic links, adopted by developers today and emerging ones like WebAuthN. We will present incorrectly coded authentication patterns observed in disclosed reports related to these schemes. Finally, we will conclude with actionable solutions to correct these flaws realized in the form of practical guidelines. These would be security design patterns that developers or designers could refer to in their daily tasks.