It's just generic stuff, there can be methods for returning Dataset, Arrays, ExecuteNonQueries, ExecuteScalar etc...
Create a class; make it abstract or virtual, also it's up to you if you want to hard-code your connection string or not.
Do not place any SQL statements or business logic in this class.
Once you set this up you will never have to fill dataAdapters, DataSets, etc, in your client code.
Sorry but I will not provide any sample code for this.