Creating Playlists on Windows Phone
Creating playlists on windows phone isn't particularly difficult, but it's not particularly intuitive either.
Clear the "now playing" playlist
When you're listening to music and select the pause button to stop the music from playing, the music stops playing but before you work with playlists you need to completely clear the "now playing" playlist on the phone.
You can clear the "now playing" playlist on the phone by powering down the phone and powering the phone back on or you can install the very useful and free "Stop the Music" app. (Click this link to download the "Stop the Music" app)
Select music for your new playlist
Open up the music+videos hub, swipe over to the Zune screen (for Windows Phone 7) or the Collection screen (for Windows Phone 8), tap music. Now select and add entire albums or individual songs to the phone's now playing playlist:
As soon as you select the first album or first song to add to your playlist, music will start playing. Press the back button and find the next album or song you want to add to your playlist. press and hold your finger on the album or song and select "add to now playing." Proceed in this manner until you've selected all the music you want to add to your playlist.
Save your newly created playlist
Now you can find your newly created playlist by tapping the music+video tile on the phone, swipe over to the Zune screen (for Windows Phone 7) or the Collection screen (for Windows Phone 8) and swiping over to the playlists screen.