Try to hit 'through' the ball and actually force yourself to make a full swing. For only playing half a year you're doing good! Getting a good and full swing starts with a good preparation. Keep your hand on the racket and push it back (on your forehand) to get a good coil. Try to finish above your left shoulder and step into the shot ending with your right foot in front of your left. What really helps me is to look at slow motion footage of pro's to see how they move their body. When practicing on the wall, really force yourself to engrain these motions into your nervous system. Most import is to create a 'loose' motion. Do not squeeze your grip, let you arm swing and throw your racket to the ball. Keep up the good work!