1. Trust your instincts
If a particular passage of music is typically played played with a clean sound and no vibrato, but you absolutely love to play it with distortion and crazy amounts of vibrato, then by all means do just that. Every time you play your guitar you should be making a statement and communicating to your audience (whether it be a few close friends or 30,000 strangers crammed into an arena) who you are as a guitarist. As long as you play your guitar like it sounds in your head, you will be emotionally invested in what you are playing and people will notice.
2. Don't be afraid to try something new
Sometimes you get the feeling that you're stuck in a rut. This could be with a particular song, or with your general approach to playing the guitar. When this happens, it is important to forge ahead with an open mind and begin to experiment. Try playing that new verse riff you've been working on with some chorus and delay. Maybe add a touch of reverb and some overdrive, or whatever you can think of that gets you one step closer to the sound you are hearing in your head.
3. Phrasing is king
How you play something is more important than what you play. Music as an art form allows you to express a variety of feelings and paint a picture through sound. Just like you can say the same sentence ten different ways and express ten different emotions, you can play the same 3 note phrase on your guitar ten different ways and express a different emotion for each. If you aren't quite happy with the way a certain song or passage sounds when you play it, think of all of the different elements that you can tweak to get it to sound exactly the way you want it. These can be subtle differences such as a faster vibrato on a specific note, or using a hammer-on instead of a slide. They can also consist of more noticeable changes such as increasing the tempo, or changing the key of the song. Once again, don't be afraid to try something new. Remember, "its all in your head," and you have to use any means necessary to bring it into reality.