Any aspiring musician needs a basic foundation to keep in mind while practicing or performing.  The following are some fundamental tips you can apply to your playing:

Relax. If you want to get good at anything, especially playing guitar, the first thing you have to do is relax.  This means releasing the tension in your body from your head to toe.  Concentrate on loosening your shoulders and neck, since these muscles do most of the work which includes supporting the weight of your axe.  Stretch your fingers out with some simple warm-up exercises before you try to tackle anything difficult.  Think of it like playing sports; you wouldn’t play an intense game of basketball without stretching your body first.  One good way to stretch your fingers is by playing chromatically up and down the neck.  You can even wedge a golf ball in between your fingers to get your joints really loose.  Now you’re ready to play.

Think sounds, not shapes. One of the most important skills a new guitarist should learn is ear training.  Lots of players memorize the chord and scale shapes from a young age, and there is nothing wrong with that.  However, the truly gifted musicians think about tones (notes), not scale shapes.  If you rely too much on scales, your playing will sound too technical and forced.  Music is not a mathematical solution; it is a much more organic process.  You can use the scales to guide the melody, but ideally your sound should be the projection of what you’re ears are hearing.

Keep it fresh. Strumming an open-A chord the same way every time can get boring pretty quickly.  A good way to develop some finesse is to approach the same things you’ve been playing in different ways.  Try hitting that A chord using a different strumming pattern.  You can also try playing the chord as an arpeggio (picking each chord note individually).  Incorporating these tactics into your playing can open up a whole new world of possibilities.  Every time you pick up the instrument you should be thinking about new approaches and fresh ideas.  Try to avoid running through the same scale over and over.  It might make you play faster, but you won’t be able to develop your own style by regurgitating mindless scales.  Practice is not something you have to get out of the way; just the act of playing and enjoying is practicing as an end in itself.

Think nothing. The best players will tell you, when they’re on stage deep in the groove, they are thinking about absolutely nothing.  A really skilled performer will even go into a trance, or meditative state which facilitates their imagination.  When you’re wrapped up in the frenzy of playing, any stopping to consider, “What should I play next?” will sink your ship every time.  Playing music, especially improvising, is the art of spontaneous creativity.  It isn’t meant to be analyzed and dissected, so let your soul come out in your playing and worry about how it sounds later.  Of course this doesn’t mean brand new players should expect to think nothing and play like Jimi Hendrix.  You have to get the basics down first and learn some technique.  But there comes a point when you have to rely on the instinct that you’ve trained through practice, and just let it fly.

By concentrating on these ideas while you're practicing guitar, you can expect your playing to progress in a natural and original manner.  You will become much more consistent and stable in your control of the fretboard.  A good foundation is what will let you take more risks, and eventually evolve your authentic style.