Watch the Survivor online guitar lesson by Jeff McErlain from Essentials: Chord Tone Soloing
Here are some music clichés that are actually pretty true: keep it simple, melody is everything, if you can't sing it you can't play it, and, tone is in the hands. There are more of course, but these ones I found to be particularly true when working on cord tone solos or music in general. I threw in the tone comment because it's just true! Notice how simple the melody is that I'm playing - that's a hard lesson to learn, as a lot of the times we just want to go for it. If you think about some of our favorite guitar solos, most of them are pretty darn melodic. I love a good shredding solo as much as the next guy, but it all comes down to melody.
Melody is what we remember as a listener - think about any Beatles song, and if you can sing it back, you know the melody. If I think about every David Gilmour guitar solo, I can sing them all back, because they're melody based. Most melodies are based upon chord tones...see where I'm going here? If you can't sing it you can't play it, and what I mean by that is if you're trying to play something melodic, you have to know what it is first before you can play at well. That's another hard lesson to learn. When constructing the solo, I wrote it primarily away from my guitar. The more you do this, the more it'll work into your normal playing.