As a Lone Wolf developer I don't have the luxury of code reviews, either on the application front end or SQL backend. I also don't have much in the way of beta tester support either. Sigh.
As a result I have to rely heavily on the compiler and static analysis tools like SQL Prompt and ReSharper to catch code smells and the like. They help--a lot--but when it comes to logic problems that's all on me. So I instrument the code, set up as many automated unit tests (and a handful of systemic tests where I can) and hope for the best, pre-release.
Which, when developing a 600,000+ line application split evenly between .Net and T/SQL, is a bit nerve wracking.
Just wish unit testing was easier to deal with. After all, when you're the only developer writing test harnesses consumes WAY too much development time. Roughly doubles it, in fact.