Most people handle the guitar like it’s a baseball bat. They grab it and squeeze the hell out of it. There is nothing more simple to understand and so difficult to learn. Learning how to relax your hands and remove tension is critical. The more tension in your fingers the more difficult it will be to make changes on the guitar. Tension binds your fingers and makes it harder to perform the small movements needed to play guitar.
Beginners are often intimidated about pressing the strings hard enough to prevent string buzzing. A little string buzz is better than the tension. With time your fingers will develop calluses and strength, and the string buzzing will go away. For now focus on being relaxed and flexible in your fingers. I start every playing session by just simply making a fist and the extending my fingers several times. This had the affect of teaching my fingers the relaxed state when my fingers are half extended. This is the feeling I look for when playing guitar.
Slow Down to Speed Up
The best method to increasing the speed you play your guitar is to SLOW DOWN. This is so true. Most beginning guitarist want to play as fast as they can, but to do this and make it sound good, you have play some notes people want to hear. Not just a jumble of stuff.
To trick to speed is being able to play the notes or chords correctly and by instinct. The best way to develop instinct is to start slow and play the notes properly without building tension in your hands and with a consistent beat. You should purchase a metronome, or I prefer a drum machine.
Set the beat at a reasonable speed and play at that speed until you’ve mastered what you are trying to learn. Sometimes it needs to be annoying slow, but it pays off with a big dividend in a relatively short period of time. Once you are comfortable playing at the selected speed, kick the speed up about 15% and then repeat the process. Before long you’ll be flying up a sliding pentatonic scale flawlessly and at unbelievable speeds.
Slow down and relax and your playing will improve faster than you think. If you want to play the guitar the rest of your life, then give yourself the time to learn.