I adopted a new method of practicing arpeggios today. It's nothing original, but it's new to me. In an attempt to apply the arpeggios I've already learned, I'm now practicing two at a time.
Until this week, I had always worked on a single arpeggio in a single position at a time. I'd go up and down at different speeds, sometimes skipping around with sequences, then switch to a different position or type of arpeggio. This is great for learning them one at a time or trying to play them efficiently, but it doesn't do much to get the right one under my fingers immediately when I need it in the middle of a tune.
My new aim is to seamlessly switch between certain arpeggios on the fly. My first task is a I7-IV7 progression, the first two measures (usually) of a 12-bar blues. I'm sure I'll find other ways of going about it, but for now I go straight up and down, as if I were running a single arpeggio, and switch every four or eight beats. If I'm on my way up when the switch happens, I'll hit the next lowest note in the new arpeggio from the note I just played, then continue upwards. The switch falls on a different part of the arpeggio fingerings each time, so it requires that I think ahead to the shape of the next arpeggio before I play it.
I was having a tough time at first, but I'm progressing quickly after all the practice I put into separate arpeggios. I plan to apply this to other common two-chord progressions such as ii-V7, V7-I, etc. I'll eventually move to longer snippets like I-VI7-ii-V7, or III7-VI7-II7-V7. I can also make the arpeggios more advanced by substituting the 9 for the root or expanding to 1-3-5-7-9-11-13. I just need to remember to pause for some real applied improvisation every day so I can work on tastefully filling the gaps in the arpeggios.