One of the not so widely discussed features of Dynamics CRM is the Sales Quota. You are bound to have missed this feature unless you have completed the Fiscal Year settings of the CRM organization.
To set the fiscal settings of the system, Go to settings Business Management and click on the Fiscal Year Settings.
Suppose you have set the following setting shown in the below screenshot.
Once the fiscal settings have been defined, the Sales Quota option is available on the System User record for settings the Sales quota of a Salesperson based on the first period settings.
You can set the Quotas for different fiscal periods as shown in the below screenshot. The fiscal period displayed in the below screen depends on the fiscal period settings in the above screen.
The Current Fiscal year tab will display the Current Year quota defined for the particular Salesperson. 
Though CRM provides a way to define the Sales quota for a Salesperson, it ends at that and there is a lot left to be done in this area. They have not provided for any Actual/Quota comparison that would be considered essential once the Quota has been defined. There is a lot of scope for developing this functionality further through add-ons.