Well, if you're not idiomatic with C# yet, that would be the very first place I'd start (by that I mean you know why you'd use StringBuilder vs. string concatenation, etc). After that, make sure you're good about commenting code that isn't immediately obvious. From that point, I'm afraid we'd probably need some samples to see where you might be going wrong or right.
I definately know some of the inner workings of.Net, such as using StringBuilder compared to string concatenation. Some of the things I need to know is what is an acceptible name for a variable based on its scope. For instance currently to describe a private variable belonging to a class I will prefix it with an underscore. Is there a universal way of denoting varibles by scope?
The standard (citing from memory) is to use Properties in uppercase (PascalCase) and fields in lowercase (camelCase) with NO prefix whatsoever but preceed them with "this." whenever referenced. parameters are also lowercase (camelCase) with NO prefix whatsoever and are thus difference of local variables by the absence of the "this.". However, this doesn't answer the static fields and Properties...