To download in 480p only:
youtube-dl -f 'bestvideo[height<=480]+bestaudio/best[height<=480]' https://www.youtube.com/paste-the-rest-of-the-link-here
For 720p:
youtube-dl -f 'bestvideo[height<=720]+bestaudio/best[height<=720]' https://www.youtube.com/watch?v=---------------
For playlist with text file containing youtube id's of what videos were downloaded:
youtube-dl -f 'bestvideo[height<=720]+bestaudio/best[height<=720]' --download-archive archive.txt https://www.youtube.com/playlist?list=---------------