How can I transfer files to my ipad from my MacBook

I can't figure out how to transfer files that aren't a part of iCloud to my iPad Air from my MacBook Pro.

Any suggestions about how to do this?

I can't even get my music to automatically sync either. Only about 20 songs out of 800 will sync and most of them are just legal downloads from soundcloud. Others were dropboxed files from friends so I don't know where most of them came from, but some of them are original works because I have a lot of friends who are music producers.

I am mostly concerned about photos, music and videos that won't transfer.