To create a list template for a custom SharePoint 2013 list follow the below steps:
First navigate to the list for which you want to make the list template. Then from the Ribbon go to List tab and from there navigate to the List Settings button. Click on the List settings button as shown in the figure below.
This will open the List Setting page and from there click on the Save list as template link as shown in the figure below:
The above step will open the Save as template dialog. There give the file name, Name and Description and if you want to include the list items then you can select the check box Include Content as shown in the figure below:
Click on Ok and it will give the successful message.
After that if you navigate to the List template then the list template will be available inside the Template sections.