Generally, the USCIS process cases in the order they are received. Click Here to see this page that shows estimates of how long each office is taking to process different types of cases. The USCIS updates this page every month (around the 15th of each month). Please note that these data may change without notice.
To check processing times for your case, you will need to know:
You can find this information on the receipt notice the USCIS mailed you.