well u can do any number of finger exercises along the fretboard to improve ur wrist and finger agility and also picking at the same time. just alternate pick all along the fret board using all combinations of finger on all frets and strings.

practice really sloooow so u need to keep ur fnger down more and u see if u sound nice and flowy or not.

Now i want more strength than that, u can try getting higher gauge strings or one of those grip things with springs - ive never tried these cus i cant find em but some ppl say theyre good some ppl say theyre not.