How do I put new music on my iphone without deleting my current library?

When I get new music that I want to put on my iphone, is there a way to only move the new stuff onto it without deleting everything i have on their already? The way i do it now is to just sync my entire library everytime i want new music. If i try to just sync the new stuff my entire library is deleting off of my phone.How do I put new music on my iphone without deleting my current library?
first insert all the music then later go to music library and click update the library......How do I put new music on my iphone without deleting my current library?
you have to create a playlist of the music that you actually want on your iphone, then once you get new music drag it to the playlist and click sync, then it will sync and you should get all your music. Make sure you remember too click sync if you don't it will not work. If that doesn't work make sure that it is all the little boxes beside the name of the song, are all checked and if they're not check them.How do I put new music on my iphone without deleting my current library?
there is a check box next to "only sync checked songs" then you check all the songs in your library you want on your iphone