Such as, a not enough releif in your neck which can be fixed by adjusting the truss rod, or the frets may not be level and you would have to get them "dressed", and or a partial re-fret
Neither of these fixes are for a beginner to perform. You need to be taught by someone that allready knows. It is likely, that unless you become a tech or luthier that you will never do your own fret dressing or re-frets. These are time consuming jobs that require knowledge and precision.
If it's as simple as a truss rod adjustment, you're in luck as that is not terribly hard to learn, and you should learn how to do it properly, but have somebody in the know show you and explain to you how it is done.
Personally, I recommend that unless you do this for a living on a daily basis, as I do, that it is better to let an experienced tech do it for you. I know that I charge more to fix mistakes by owners than to fix the original problem, and a couple of my luthier buddies feel the same way.
And change your strings man! :eek: that just gross! lol (kidding...but not really)