When you need to put an empty string in C#  or ASPX code, use String.Empty rather than “”, since this saves creating an object for every appearance of “”.

When checking for empty string, create a utility method like !Util.NullOrEmptyString(s) instead of (s != null && s != “”).  It’s more readable, and one is less prone to forget that one usually has to check for both null and empty string.