There are a couple ways that you can accomplish this. First and probably the easiest, is to assign the user accounts to one of the built-in security groups that would meet the criteria of what you want the users to do, such as ‘Local Administrator’ group, Domain Admins, Backup Operators, etc.
The other option would be to delegate administrative permissions through AD. You can do this by right-clicking on an OU within AD and select the ‘Delegate Control’ option from the options menu. This starts the ‘Delegate Control’ wizard which will walk you through the process. This option will allow you to get very granular in way you can grant a user rights to perform select administrative tasks.