female - note the smaller pre-anal pores and lack of hemipenal bluges after the vent. Some females CAN have slight bulging after the vent.
male - note the enlarged pre-anal pores, with waxy secretion and hemipenal bluges after the vent.
+1 on Elizabeth's suggestion too! Much of your questioning has been hashed and rehashed through numerous leopard gecko forums, including here. Check for sticky posts (marked as Sticky and positioned at the top of each forum/sub-forum) as these are typically set aside as a means of answering "beginner" questions. The search function is also your friend. ;-)