Hmm my daily doodle routine (more like habit to be honest) is to have my sketchbook open and ready while I'm browsing my tumblr dash or pinterest, and as soon as I see something neat I do a quick scribbly doodle of it.
Also I think it's prob a good idea to draw stuff that's within your comfort zone, such as headshots or eyes or your favorite characters etc. If you feel really rusty it's better to draw things that helps you get back that feeling of enjoyment in drawing.
The longer "break" you've had, the easier and basic should the exercises be. heck most artists needs to re-read the basic stuff every now and then to keep their knowledge fresh.