You can't really damage a server, unless you use the FSO object to delete all the files on the server, but you can effect performance in allot of ways.
Each time you create an object it uses resources, try to reuse things like recordset objects on a page as amuch as apoossible.
Also remember each time you use an object whether to connect to a database, or to send an email, etc. remeber to release the object after use, thuse freeing up server resources that may other wise slow down the ruuning.
Also things like session variables use allot of resouces, so try to avoid these on busy sites.
Things like the path to the databases could be stored in application level veriables, which saves on the amount of variables used within the site.
Each variable you create will use up resources, but these are quite mimimal so don't worry to much about this.