Good points about chord melody. I found Robert Conti's materials to be a good resource, but certainly not the only resource as many folks have found their own way. Conti has two books with DVDs that are focused on chord melody.
The first "Chord Melody Assembly Line" gives you a chord vocabulary to harmonize any melody note with each of the chords in the harmonized major scale, including b5/#5 and b9/#9, etc. These are very easy to memorize because you are essentially taking each chord and then playing it under each possible melody note. He does this with C maj, F maj, D mi, A mi, G7, and then runs through the augmented and diminished chords. He takes you through doing a chord melody of "Oh Susanna" in sections as he takes you through each chord, culminating in the whole song. He then has you do that to "Danny Boy", and gives you the entire arrangement to check your work.
The second book, "The Formula" shows you to change the harmony under the melody so that you never have to play it the same way twice. He uses the chords you learned in the first (Assembly Line) book. This opens up the whole world of harmony to you, which is where chord melody gets really interesting for the player, as the previous posters have described quite well.
Another approach is from Rich Severson at Guitar College. He has a course on arranging fingerstyle jazz guitar. He starts out with having you play chord inversions on string sets, which is the more typical way that teachers approach the subject, and then goes through all the various vehicles such as walking bass lines, substitutions, moving lines, etc. This is a very well thought out course and is compete as shipped. In his course, Rich Severson makes a distinction between "chord melody" and "fingerstyle". He teaches you to do chord melody first, and then goes into what he considers fingerstyle. For him, chord melody is rather static (obviously not how Joe Pass sees it), with chord and melody . For Severson, fingerstyle is moving lines and attention to individual voices, more along the lines of "horizontal" thinking rather than "vertical" thinking.
Some of us prefer to work from a guided course of study, and others are more DIY. The comments in both of my posts are not intended to argue or diminish in any way what the other posters here are saying. It is all good. I am simply providing the "book learning" approach, since that is what I have done that worked well for me.
My first post was about the Bill Munday book, which really results in a more classical sounding arrangement, which is quite different from chord melody. Though the title indicates "chord solo", as it progresses it is less and less like that. in other words, he starts with a more "horizontal" thinking approach and progress to a more "vertical" thinking approach, much like Rich Severson but a bit more basic.
Here is another approach (again, books)... Barry Galbraith. Mel Bay has two books of Barry Galbraith chord melody arrangements. Each comes with a CD of every tune in each book. The CDs are great to listen to on their own (except the tuning track...), and the arrangements are really fun to play. You can learn a lot from these arrangements. However, as I mentioned in my previous post, I think it is better to be immersed in arranging on your own first so you know what you are looking for in these arrangements, rather than just memorizing them to recite when you pick up your guitar.
I almost always work from a fakebook, as others have mentioned, but also will figure out the chords and melody from a Youtube video. Not all tunes are in fakebooks, but hearing them and figuring out what is going on is a good exercise too.
To me, it seems we each have our own learning style, usually a combination of ways we take in information. The problem I always have when self-teaching is that I want to start at the beginning and work my way through a step at a time. In self-teaching, we don't know the territory, so it is like going into the Alaskan wild without a guide - we can get lost and even give up altogether. for me, the books I mentioned have been valuable guides so I don't get lost. Certainly, that is not the only valid approach, as the other posters have described very well. Hopefully, folks reading this thread will get a variety of ideas and be able to choose the best path for them.
I really don't play "classical guitar" as it is widely approached in this forum. What I do is what is being discussed in this thread, so it is finally my turn to say something that might be of some help.
That said, my absolute favorite form of what we call "guitar" as an instrument is the classical guitar. It is the perfect instrument when built well. I feel extremely grateful to have found such an instrument and rekindled my first love with the guitar.
Edit: Joe Pass has two CDs on which he plays chord melody solo on a classical guitar. I strongly recommend you give these a listen, and then do it again and again. "Songs For Ellen" and "Unforgettable" are the two albums. Of course, tehre are other players too such as Ralph Towner who has a couple of solo albums, and so do a number of other players. It would be worth your while to seek these out.