It's a good idea to use a class say gateway where all
database access codes will be written.in this gateway class
you will implement db connection as follows -

first create another class -

Asp.net caching helps you to create high performance applications.
you can cache objects like DataSets,or your created objects.you can
also do page level caching if you used user controls in the page
if your aspx page includes lots of work.

beginners of .net programming can't guess sometime that
how easy is sending mail through .net.there are many ways
to do that.but i am writing here the easiest method to send
mail in c# with .net.It doesn't involve a lot's of coding.
all is built in and no more components.

in coding giving proper names to methods,classes,controls,
variables,others is neccessary and good programming practice.
think that a method name-show button click.