Start with 3-strings sweeps , it will get your picking hand familiar with the sweeping technique so you can focus more on your fretting hand on 4,5 & 6 strings sweeping later ... It worked well for me.

Learn basic major,minor & diminished sweep shapes first.

Check out this link for examples : http://www.guitartricks.com/forum/showthread.php?threadid=6272&pagenumber=lastpage