Good advice above.
As far as chord tones go, know where your 1st, 3rd and 5th are (major and minor 3rd!) for all chord shapes. Learn what each sounds like within the context of the chord. This way you’re not just playing “safe” notes that you know won’t sound bad, but actively seeking out the notes you most desire.
Same goes for notes that define extensions and augmentations. Like the dominant 7th, major seventh, etc. Use those to color your leads within the context of the chord.
And work on grace notes. Jerry played a lot of approach notes. He didn’t just nail the target note, he approached it from a nearby note (or notes,) then landed on it. These are often half-step chromatics from either below or above the target note.
That ought to keep you busy for a while! Just make sure and keep it fun.
Oh, and if you’re not already familiar, check out Michael Palmisano's Youtube channel, especially his analyses of some Dead performances. He does a good job of breaking down what’s going on.
https://www.youtube.com/channel/UC5rPp4 ... qnRCZ_RkPA