T-SQL Coding Standards
Here is a nice collection of useful T-SQL coding standards: T-SQL Coding Standards.
Note that these are by no means the end-all of coding standards. Each person has their own style and convention, but following an agreed standard helps everyone involved in the team (or organization) easily understand code that has been developed by a collegue. So feel free to invent on top of these. In my case, our organization has a subset of this, but after seeing this article, am planning to expand more on the list that we have.