how do I enable sudo?

[Gregg Dinse]

Hi,

For years my main account was an admin account and I could use sudo.   
A few months ago, I decided to try to be a little more secure.  I  
created a special admin account and then I made my main account an  
ordinary user (i.e. non-admin) account.  I just tried to use sudo  
today (from my ordinary user account) and realized that I could not  
do it.

Can sudo be executed from an ordinary user account?  If so, how do I  
do it?

When I try to use sudo, it asks for my password (as expected), but  
after I provide the password, it says I am not in the sudoers file.   
If it's possible, how do I add my ordinary user account name to the  
sudoers file?

Thanks in advance for any help you can give me.

Gregg