If you're a guitarist, you're probably always trying to find something different or interesting to do with you solos, fills, and riffs. If you're not, it's probably a good time to start, or else your music will become stagnant and repetitive. So with that said, let's take a look at some ideas that might help you out of a "un-creative" rut.
New Ideas From Improvising
A good thing to try if you are seemingly out of ideas is to play along with the radio. This is good for you because you learn to quickly adapt to whatever song is playing, even when you have no idea what's coming next. If you don't already know the key of the song, start on the low open E string and ascend chromatically until you find that note resonates perfectly with the song. Note that some songs' keys are harder to figure out than others. In "Photograph", by Def Leppard, it is nearly impossible to determine the key. The reason being is because the recording is actually slowed down. Don't get discouraged if you can't find the key at first. No matter what song comes on, try to play over it while keeping the same feel of the song. For example, if "Sweet Home Alabama" came on, you would probably use G major pentatonic to keep that almost country vibe of the song. But you wouldn't play fast and scary shred because it doesn't relate at all to that particular song. On the other hand, A major pentatonic wouldn't fit over "Bark At The Moon"; but lightning fast shred would be perfect.
When you're improvising, try to start by playing licks you already know, but also be really open to doing some crazy out of the box stuff. For instance, try 1 1/2 step bends, slide up to a note that is out of scale and bend to a note that's in key, etc. I find that when I sort of "let go" when I improvise, I sometimes play a lick I didn't conciously think through, and it sounds cool and different and I go back and figure out how I did it. That can be a good source for original licks.
A Different Approach To Chords
When trying to write a new song or establish a new chord progression, instead of just falling back on G, C, D; E, A, D; or D A B G, start by establishing a key, say A major. Now, make your own chords using notes from the A major scale. If it helps, trying to come up with awkward finger combinations, so that you don't just end up with chords you already know. Try mixing the chords you come up with with standard chords that fit in A major. Or try to totally avoid the chords you already know. If you don't know the major scale and it's modes, you can also form chord shapes form the A major pentatonic(also F# Minor Pentatonic) Either way, try to break free of any repetitive habit's you may have accidentally obtained.
Once you come up with some chords, instead of just strumming them all day, try to arppegiate them. Not nessecarily sweep picking, just playing the notes of the chord seperately and mabye doubling or tripling them. If you happen to come up with a really terrible sounding chord, try to isolate the dissonant note and skip it when you play the arpeggio. Also try playing the notes on a singe string. This works best if your chord is a type of E, A, D, G, or B chord.
Finding Your Scales
Perhaps you are stuck in a one, two, or three octave box of a scale. How are you going to break free of that? The answer is really quite simple. Make a guitar neck diagram with frets zero through twenty-four. Now figure out the notes that are in the scale you are stuck in. Write those notes down (you should only have seven). Now mark on the diagram every place those notes occur. When you are done, you will have a diagram that shows you every note you can play when working out that key. This idea works with every mode and the pentatonic scales (you should only have five notes in the pentatonic scales). If you don't know any scales, it can also work if you come up with your own scale.
If you learned nothing else fom this article, please realize that expectations for a good song are at an all time low I.e. Everybody is just doing what's already been done. Don't follow the crowd. Bring something new to music. Do something different. If you come up with some really amazing lyrics, don't ruin them by playing G, C, and D under them. Be original.