You can add an Account quickly and easily from any (V3) screen in SA by clicking the Quick Add icon in the navigation bar then selecting "Account":
The Add Account dialog is very simple and will vary based on your tax and validation settings:
Select an Account Type - Client or Lead. Enter a First Name and Last Name. This will automatically update the Display Name field. Begin typing a Service Address and select the correct option from the populated results. Enter a Property Name and Name on Invoice. If you have Sales Tax enabled, select whether the Account is taxable and click Save.
The Review Account overlay will automatically be opened for you if you are on the Accounts screen when creating an Account. To enter additional information about the Account, click Edit:
Any tabs that have required fields to save will show a red icon at the left. Click on each tab and the required fields will be highlighted in red. These fields may depend on your Validation Settings. You will not be able to Save the overlay until all required fields have been filled. To save changes, click Save Account in the lower right corner of the overlay.