And this kind of summarizes the majority of things that have been said already . . . have you had your guitar set up recently? That's when they check the action, intonation, fret wear, tuners, connections, etc . . . clean, polished, and change your strings. Unless you know your guitar is in perfect shape (and can adjust the action yourself as climate changes) I would recommend taking it in for a set up at least once every 6 months . . . I take mine in more often than that, as mine sees a lot of heavy playing, travel, and climate chances, and I dont want to trust it to my own hands . . . should cost $25-50 plus new strings. Well worth it.
I did a live session one time where I was having trouble tuning my guitar beforehand . . . turns out in the week of travel and rehearsals my action had gotten knocked badly . . . I learned my lesson then!
