These exercises are designed to tighten up your playing in a couple of fundamental areas.
They're born out of an analysis of my own playing, and so it's hard to say whether they'll be as beneficial to you as they have been for me. My advice would be to take the essential concept, and adapt it to your own needs, or just change it in a way that makes it feel as if it's something you yourself created. This should make them feel like less of an imposition, and more of an aspect of your own natural development. I believe the exercises we create for ourselves are the most effective, even when they've been remoulded from an existing set.
Hands separate is a practice technique associated more with piano than guitar, but it can be useful to use it for guitar practice. The picking and fretting hands have two distinct jobs: the picking hand behaves like a percussionist, and the fretting hand is more like a keyboard player. The two hands have to be in sync with each other while remaining independent; kind of like a two piece band. They behave more like a duo than a single individual. This is one of the things that makes guitar playing a challenge.
The below exercises are not entirely hands separate, it's more a case of the hand without focus having a much reduced role. The exercises can be completely hands separate, but it makes the picking exercises duller to play, and the fretting exercises harder, so by giving the other hand a bit to do we're just making life a little easier.
Picking; The Percussionist
Pay attention to what the picking hand is doing. The fret pattern is just something to do that comes easily enough that you don't have to think about it. Feel free to play any fretting you like because it's the picking that we're practicing.
This is a sixteenth note exercise. Play it at whatever tempo you feel comfortable. I'll write them out first, then talk about the point of them, and how they can be expanded to create a full workout.
So you can see that they all contain four notes, or because we're focussing on picking, four strikes of the pick. It's a sixteenth note exercise, so it's 1 e & a etc. So the point of the exercise is to practice maintaining fluency while crossing back and forth between neighbouring strings in a variety of ways. It's pretty easy to play fluent sixteenths while staying on a single string, it's the string crossings that tend to disrupt flow so that's what we're practicing.
To expand each exercise, simply play it once starting at the first fret, then move it up a fret to the second., and play it again. Keep doing this until you get to at least the twelfth, or even to the end of the fret board. Then move down to the next pair of strings, A-D, and repeat, this time descending until you get back to the first fret. Continue in this way until you run out of fretboard. Do all 14 exercises, then reverse the picking by starting with an upstroke, and do them all over again.
Depending on where you are with your playing, you might need to play these at relatively low tempos. If so, you might want to trim them down a bit. You need to strike a balance between creating a comprehensive set of exercises, and completing them in a reasonable time. You don't want to be spending too much time on these sorts of things. You certainly don't want to be so tired or bored by the end of the first two that you never get to do the rest.
On the subject of tiredness, even though the above fretting patterns are 5' chords, they're not played as chords, they're individual notes. You don't hold both notes down the whole time like a chord because you'll wear out your fretting hand. When playing the notes with the first finger, the third is in position but relaxed, and vice versa. Fret the notes only when they need to be played, and at no other time.
You can elaborate on the above picking exercise in whatever way you like. For instance string skipping, more strings than just two, etc. I definitely recommend mixing up the exercises to create a varied pick pattern. This is of course a little trickier than just maintaining a single one, but it is much more like the sort of thing you'll encounter in normal play.
Fretting; The Keyboard Player
You've probably seen exercises such as these many times in relation to strength and agility, fluent legato etc. They're included here because they make the fretting hand totally responsible for timing; just like a keyboard player. There is a temptation as a guitarist to just clamp down the strings, and leave it to the picking hand (percussionist) to sort out the timing. We can become pretty sloppy as a result, and the two piece band sounds lousy because the percussionist is hitting things before or after the keyboard player. So the below exercises should sharpen up the fretting hand's sense of rhythm. Focus on timing above all else. I'm going to write them out in the same stripped down way as with the picking exercises. You can expand them in whatever way you like.
Finger 1 plays everything on the first fret, finger 2 on 2, 3 on 3 etc. I tend to do the weakest fingers first so that as the exercise progresses, and you become more fatigued, it gets easier. Doing it the other way around tends to lead to the neglect of the fingers that need the most work.
You can play the following exercises as eights, sixteenths, triplets, sixteenth triplets, or any combination you like. As long as the fretting hand is responsible for timing, it doesn't matter too much.
The first note is picked, but if you want to be really tough on yourself, you could tap instead.
E|4p3h4p3-| repeat as necessary
A Word About Boredom
This shouldn't feel like punishment. It shouldn't be like doing lines at school. You know how it feels as a school kid to have to write out I must not forget my kit 100 times. By the fifth line you're mind is rebelling and your body is squirming.
The reason these punishments are so tortuous for us as children is because at that age we have a very low boredom threshold.
When I first started doing these sorts of rather dull and repetitive exercises I was an adult, and yet I still found myself squirming within 5 minutes of it. It's definitely something you have to ease your way into. So if these sorts of things feel too much like lines, do them in small doses, and just allow your tolerance to increase gradually. My advice would be to have your guitar ready to go at the flick of a switch, and just pick it up and do some of these 'lots of work and little gratification' type exercises several times a day.
Hope this is of use to you, and not just a lot of waffle about a couple of simple ideas.