K.I.S.S.

Keeping it Simple

||: C - - - | Dm - - - | G - - - | Dm7- - - :||

Try playing this progression and throwing licks in based on the C major scale:
C D E F G A B C
Occasionally, throw in a Bb transition note.
See how that works for you.

You have to know a bit of theory, and then feel it!

Practice Practice Practice

Make sure that you practice today.  Pick up your guitar for at least 5 minutes a day (which will typically turn into many more minutes once you have it in your hands and playing).  Remember to use back-and-forth picking style when you play your scale runs, play everything slow and 'clearly' and build up your speed gradually as you go.  Finger your chords so that 'all' the notes ring clearly without any buzz.  Mix up your practice material, styles, and such so that you stay interested in playing.  Get a practicing partner to jam with, as this will help you both!  Most of all, have fun!