What are the security concerns I need to consider while coding?

Question

I know SQL Injection is one... what are the others...

Answer 1

I like to model my system with Threat Modeling Tools. This particular one lets you model different applications and gives you all types of information about what types of threats are applicable based on the model as well as some mitigations and their risks. It also let's you track these risks throughout the dev. life cycle to come up with mitigation plans. It's pretty cool. :)