"To reduce and optimize the conflicts between your plugins, you need to order them by priority. You can do that manually, but it takes a lot of time, and not recommended. What you can do instead is to download the application LOOT (Load Order Optimization Tool)."

What does it do?
• Shows the type of plugin (ESP, ESP-FE, ESL, ESM)
• Shows dirty plugins that need to be cleaned (the next section will explain how)
• Shows redundancies
• Shows recommended patches
 

How To Use LOOT:

I - Download LOOT

II - Link LOOT to Mod Organizer 2

III - Launch LOOT through Mod Organizer 2

And now your load order is organized! I advise you to do that every time you install new mods containing plugins.