Not that I'm a proficient guitarist, but I can say that putting emotion in music is the same as putting emotion in speaking. You can simply utter the words "I love you" and there's absolutely no emotion, and the same words said differently take on a whole new dimension.
Do you have an ability to speak with emotion/ If you do, that centre in your being from which your spoken emotion emantes is the same one from which your playing emotion will emanate. Just you mean to speak with feeling when you mean, so will you play with feeling. You "switch the centre on". Play as if your guitar was your voice.