That's a good question. In my own (undisciplined) way of learning, I would take one of the approaches recommended here, or maybe two of them and give it a try.
Maybe this only works for me... but, I woudl probably make some progress with that effort, and, being unsatisfied with it, I would stop working on it for a while (actually until you can completely forget what I was trying to do). Then, when it occurs to me that I haven't done that for a while, while playing a familiar tune (one that I may have worked out a few things for), I will try a phrase as chord melody (or whatever technique I'm interested in learning), just one short phrase. Then each time I play through the tune, use the new (chord melody) phrase. Just one phrase in one place - until I start to get comfortable with it.
That's how it starts (the second time) with a promising sound/phrase to anchor it down.
As I said, maybe I'm the only one who learns that way, but I doubt it
For chord melody/solo in particular, I find that (another long way around the barn...) it appears easier to me after I have learned the tune in fingerstyle cords (arpeggiating every chord - until it can be played smoothly/in rhythm and comfortably - so it is swinging or shuffling or whatever kind of movement is natural for the tune - then it's easy to chord melodize, you just 'claw teh bottom 2 or 3 notes together like a 'regular' chord and play with 1, 2 or 3 notes on top for each pulse underneath, That gets you two or three parts happening - depending on how active the bass line sounds.
I hope you find this useful. If not, at least there's something to think about (for both of us).
Rich