In addition to the built-in Odoo modules and the various settings that can change the way Odoo functions, there is also a growing collection of custom Odoo modules written by the community. When you find a business requirement in which you believe you might need to make some custom module development, take the time to go to the Odoo application repository and search for modules that could perhaps fit the purpose. Even if the module is not exactly what you are looking for, there can often be a lot of valuable code in those modules that can help you with your own module development.
You can find the Odoo application and module repository at https://www.odoo.com/apps.