I have several items that I either unpublished or deleted from the K2 items area. These items are still showing up on the live site. I am new to Joomla and I double checked the cache, but unless there are other areas that I am missing, I am confused as to why these changes are not propagating.

Hi. Joomla! caching has many layers. When you save an item the component cache of K2 is being cleared. But there are also, the cache of the modules, the page cache etc which are not cleared. So you first need to find what type of cache are you talking about. If for example it's a module cache you can set it to expire sooner.

Ok, thank you! Are there dummy proof tutorials out there that can help me with this? I believe I turned on the site conservative cache, cleared the cache in the maintenance and changed the cache from 900 to 100 on the module manager. So confused!

Try turning off the module's cache to see if that changes the module's content.