In your control panel follow these steps:

1. For WebPro hosting accounts, click on the System tab. For OHP hosting accounts go to step 2.
2. Click on Limits. These are the limits for your entire account. These can be allocated to your domains as you see fit, as long as the total of any given resource between all of your domains does not exceed the limit for your account.
3. Write down the limits for each resource.
4. Click on Up Level.
5. Click on the domain for which you wish to set limits.
6. Click on Limits. These are the limits that have been set (or not set) for your domain. Set these values to the limits that you wish.
7. Click on the OK button.
8. If you receive a message that "Some fields are empty or contain an improper value" you will need to pick a smaller value for whatever field is highlighted. You can also go to one of your other domains and lower the resources so you can add more resources to this domain.