For beginners - how to start, what to play
Are you someone who gets bored easily with running scales and chord progressions up and down the guitar neck? Tired of the mindless and often arrogantly written exercises in music books or on the internet? You only dabble in reading sheet music, or sick of the inaccurate TABs you try to learn note for note just to realize it's not even close to the original? Then it's time to stop. Quit hard practicing for a while, because in my experience hard, cold practice will hardly translate into fluid, soulful playing, at least for certain people, and you might be one of them.
I suggest you to try to play simple, single melody lines first. It's always useful to be able to draw figures with a few simple lines before you try and paint a new Mona Lisa. You can start with some children's songs, folk songs or the melodies of tunes you like, or really, whatever comes to mind. Approach them nonchalantly, the way you would hum them to yourself in the bathroom or in the car, only this time, try to recreate it with the guitar in hands.
Search for the melody notes on the fingerboard patiently, just like when you started to learn typewriting, then play those notes one after the other. Don't rush, give yourself time to progress slowly and steadily; enjoy the process. Practicing this way, you will be rewarded instantly when you are able to play through a tune the first time.
When you are already able to play a few melodies this way comes the next step: embellish your playing. One of the simplest ways to do that is to try and add vibrato on every note. Play the songs slowly and shake the strings under your fingertips, try to add some feel. Remember, you are trying to recreate the feel of humming these tunes, so try to vibrate, bend or slide to the notes a similar way you or the original performer would sing them. It's not always possible in every case, but keep trying. Be creative!
Don't forget, playing guitar or any instrument should never feel like a hard and tiresome work. When you feel exhausted and don't progress anymore, quit playing for a while; put down the guitar and do something else. Playing music is supposed to be fun, and you learn the most if you are able to keep it in the "fun zone". Enjoy!