3 Note-Per-String Exercises
The 3 note-per-string concept is a shredders delight. These shapes allow you to create extremely fast runs across he fretboard a.la Paul Gilbert, Steve Morse, Vinnie Moore. Make sure you follow Alternate picking (down-up) strictly. This approach will enable you to get across different strings without loosing right hand-left hand co-ordination & without having to adjust your picking for different licks.
Chromatic Exercises
Chromatic scale provides arguably the best possible exercises to develop Speed, Accuracy and endurance while playing the guitar. Below are a few exercises that will surely help you gain a lot of control over your guitar. Do remember, they are not the most melodic sounding exercises, but definitely one the most helpful if you are looking to build your strength. Do try to attain the tempo mentioned on the sheet. Start off by playing slowly in time, making sure you reach the desired speed over a period of time.