Okay, so this will be short and sweet. It's just something that I have noticed, and thought should be mentioned somewhere on the sight because it works. Now everyone tells you for your lead you should use scales, whether they are pentatonic, or modal scales. Also, I'm sure you know you will want to stay in key. But what I have noticed in my playing, is that if you use the scale degrees, and specific scale degrees of your chords for what I call accent notes(like where you put your string bends, or notes that get a full count and what not) your melodies, or solos when you get to that point will sound much better and you will develope a better control of that sound. What I mean is, say you have a common A5 power chord. This chord has no third scale degree, and so your melody is free to determine the major or minor feel. I love the sound of Am so I will apply it using my scale degrees. The scale degrees for Am are easy to remember because they spell ace. They are A-C-E, in the order of 1-3-5. Now that C is really a flatted third from a major because chord construction is almost always based on the major scale regardless of the key. To give a minor feel to your A5 chord here you simply pick an a, c, and e, out somewhere on your fretboard, and you can do this with no knowledge of scales at all, then you use them for a short melody, maybe using slides, bends, and vibratos. When you move to your next chord, simply change the scale degrees you are using. But remember, if the chord being played has the flatted third, and you use a perfect third in your melody, the notes will clash badly, and give you sour notes. This is another reason why scale degrees are so important to learn before you solo. Below the A5 chord and a simple melody using Am scale degrees are shown so you can try this on your own and see what I mean.
A5 simple melody based on Am.
Now I didn't take the time to even place this on a guitar, but it will harmonize, and even though I haven't played it, I bet it will have a sad sort of sound. The only notes I have used here are all A-C-E. The A and E are already in the A5, and I gave it the minor sound when I chose the C there on the 8th fret of the bottom E string. Oh yes, and the tuning is standard E. My personal favorite. Let me know if you would like to know more about applying scale degrees, because I'm not really sure what others will think of this quick lesson, but will give more if you liked it. Later shredders.