1. Get a metronome, most music recording/composing software has one.
2. Unplug the guitar.
3. Don't ever lift your picking hand.
4. Start off slow with a slow tempo. Against all recommendations, I suggest learning 5 string arpeggios first, because they really develop the sweep picking motion that lacks in a 3-4 string sweep arpeggio. After you get 5 strings down, the smaller arpeggios are like cake, and the monstrous 6 string arpeggios are a small transition. I'll quickly tab out the stereotypical beginner arpeggio every sweeping guide recommends. It has a little of everything, from the rolling motion, to various hammer ons. It lacks a little left handed finger coordination, but that will be hammered out in the 3 string arpeggios.
E|-----------12h17p12------------
B|---------13--------13----------
G|-------14------------14--------
D|-----14----------------14------
A|12h15--------------------15p12-
E|-------------------------------
5. Once you nail the sweep picking motion, and can cleanly play every single note without the predecessing note ringing out, begin speeding up the metronome. Start with a slow tempo. Once you can play it at that speed for at least 3-5 minutes, kick it up 10-15 beats, and work your way through that tempo. Keep working your way up until you find a tempo you struggle to play, and then practice. For hours. Next day, work your way up to that tempo and continue where you left off, until you can play the arpeggio at that tempo cleanly. Repeat as you move up in tempo. 2 weeks and you'll be shredding arpeggios like a madman.
6. Make sure your right hand sweep picking motion is always in sync with the left hand as it moves up and down the neck. This is what will make playing arpeggios fast extremely difficult for the first few weeks practicing. Once you get it down though, sweeping is seriously the most stupidly easiest technique on guitar. Way overrated.
7. Heres a three string arpeggio that doesnt have complex fingering, in case the 5 string is too overwhelming. This is a shorter version of it that doesn't include the difficult roll down fingering.
E|----12h17p12----
B|--13--------13--
G|14------------14
D|----------------
A|----------------
E|----------------
I bet the thread OP can already sweep pick; LOL. So pointless in posting this, but whatever.