Laser level for ceilings & walls?

I'm currently on a job where we will be doing "Stripes" throughout a whole bathroom. Ceilings and walls. I bought a bosch 30ft laser level hoping this will come in handy for lining everything up. To be honest, I haven't had a lot of experience with a laser level. Just old school level and measuring tape.. Seems pretty straight forward for the vertical and horizontal stuff, however getting the ceiling lines straight seems like there may be a trick to it. First off you can't point the laser upwards.
Anyone have any tips/pointers? I'm assuming maybe measure the ceiling first and just find a straight line to work from?
Obviously need the walls and ceiling stripes to "line up".. Also would you use pencil and a straight edge to mark your laser lines or just tape right on your laser line without pencil? Do I need a better Laser?! Only paid $80 for this one..