Sometimes when learning the guitar, you feel like you have become stuck. Most likely in the beginning stages you focused on the left hand making chords or playing notes on the fretboard. There are some right hand guitar techniques that are a little more intermediate that you could start to focus on to become a better player.
Muting - Muting is where the right palm mutes individual strings or all the strings. It's done by laying the right palm across all the strings lower on the guitar then stretching your fingers with your pick and still strumming or picking at the guitar. This changes the sound that you produce significantly. It's gives more of a rough and silent sound that is useful for certain songs. It's also makes the strings individually have a distinct difference.
Picking - Whether you are picking while muting or picking alone you can try advanced picking exercises. This would be creating a random pattern to follow as you try to increase your speed without losing accuracy. You can also invest some time into finger picking. While this is associated with classical styles or bluegrass, it's another avenue to train the right hand.
Wammy Bar - A wammy bar gives an electric guitar a very different sound than anything else. This is a fun technique. It helps if you are good at tapping with the left hand so that you can bend the sound with the wammy bar. The only thing not liked about them is that your guitar goes out of tune fairly quickly.
Finger Style Techniques - There are many different ways of picking the guitar with your fingers. Some use thumb picks and finger picks while you can also just use your natural fingers as well. There are many styles that you can learn for this technique. Any of them will give you a new challenge.
If you are past the beginner stages of guitar, you need something more complicated to help you get better. Learn what techniques will challenge you while you learn how to play.