iTunes – How Loved Metadata Syncs

Your iPhone is bound to a specific machine. It won't automatically sync to a machine. You have to manually force it to sync. When you do this, it will ask if you wish to erase all data on your iPhone and sync with the new machine.

Beware, if you do this, it will wipe your contacts, music, apps, videos, etc, and replace them with what is on your current machine. The only way to avoid doing this is to copy your entire iTunes library folder from your old machine to your new one, and replace the existing library.

To summarise, the iPhone thinks your new laptop is a new machine, and so won't automatically sync to it until it's re-associated. Any questions, just shout.

You could use iTunes DJ. Select the playlist that you want from the list in the left-hand corner.

Then, you can right click on a song, and select "Play next in iTunes DJ"